ACTA Vol. 197, 15 Sept. 2020, P10-19

This present work simulated the coherent BCC/B2 microstructures existing in body-centered-cubic (BCC)-based Al-Ni-Co-Fe-Cr high entropy alloys (HEAs) in light of the phase-field method. These coherent BCC/B2 microstructures contain spherical or cuboidal nanoprecipitates, or exhibit a weave-like spinodal decomposition in experiments. Based on the Chan-Hilliard equation, a two-dimensional phase field model was established using the COMSOL Multiphysics software to reveal the coherent microstructural evolutions of the present HEAs. It was found that the simulations of spherical/cuboidal nanoprecipitations and weave-like spinodal decomposition are well consistent with the experimental results. Both the lattice misfit and the anisotropy difference of Young's moduli between the precipitated phase and matrix phase affect the precipitate morphology, in which the cuboidal nanoprecipitation is especially susceptible to the modulus anisotropy. The coarsening behavior of precipitates is also discussed with the aid of the simulation results. The phase-field simulation will provide an important technique to predict the microstructural evolution and to assist the composition design of new HEAs.

ACTA Vol. 197, 15 Sept. 2020, P20-27

High entropy materials, which include high entropy alloys, carbides, and borides, are a topic of substantial research interest due to the possibility of a large number of new material compositions that could fill gaps in application needs. There is a current need for materials exhibiting high temperature stability, particularly oxidation resistance. A systematic understanding of the oxidation behavior in high entropy materials is therefore required. Prior work notes large differences in the thermodynamic favorability between oxides formed upon oxidation of high entropy materials. This work uses both analytical and computational thermodynamic approaches to investigate and quantify the effects of this large variation and the resulting potential for preferential component oxidation in refractory high entropy materials including group IV-, V- and VI-element based alloys and ceramics. Thermodynamic calculations show that a large tendency towards preferential oxidation is expected in these materials, even for elements whose oxides exhibit a small difference in thermodynamic favorability. The effect is reduced in carbides, compared to their alloy counterparts. Further, preferential oxidation in high entropy refractory materials could result in possible destabilization of the solid solution or formation of other, competing phases, with corresponding changes in bulk material properties.

ACTA Vol. 197, 15 Sept. 2020, P81-90

Refractory high entropy materials have garnered significant research interest due to their potential ability to fill a need in high temperature structural applications. However, challenges remain with respect to designing for oxidation resistance. A knowledge gap exists with respect to a rigorous understanding of the mechanisms driving oxidation processes unique to high entropy materials. This work provides an experimental complement to a companion publication, which outlines analytical and computational thermodynamic approaches that are envisioned to aid the design of refractory high entropy materials containing group IV (Hf, Zr, Ti) and group V (Ta, Nb) constituents. In this work, (Hf_0.2Zr_0.2Ti_0.2Ta_0.2Nb_0.2) carbide and diboride specimens were exposed at 1700°C in 1% O₂ for 5 min. Experimental results show good agreement with the computational predictions for the same temperature, despite differences in the overall morphology of the oxidized regions. The carbide formed porous oxides, while the diboride formed a denser external scale. Oxidation products are dominated by group IV oxides, depleting the underlying materials, which were found to consist of primarily group V carbides and borides respectively. The results provide a first look at the oxidation of high entropy UHTCs at ultra-high temperatures and validate the preferential nature of high entropy material oxidation predicted by the computational approach developed for the study of this new class of materials. 

ACTA Vol. 197, 15 Sept. 2020, P28-39

Oxides, hydroxides, and other surface films act as impediments to metallurgical bonding during cold spray impact adhesion, raising the critical adhesion velocity and reducing the quality of the deposited coating. Using a single-particle impact imaging approach we study how altering the passivating surface oxides with exposures to various levels of heat and humidity affect the cold spray critical adhesion velocity in the case of aluminum. We analyze the thickness, composition and microstructure of the passivation layers with transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR), and correlate our observations with a direct measurement of the critical adhesion velocity for each surface treatment. We conclude that exposures to temperatures as high as 300 °C for up to 240 min in dry air, or to room-temperature with humidity levels as high as 50% for 4 days, have negligible effect on the surface oxide layers, and by extension do not affect the critical adhesion velocity. In contrast, ambient-temperature exposure to 95% relative humidity levels for 4 days increases the critical adhesion velocity by more than 125 m/s, approximately a 14% percent increase. We observe that this distinct change in critical adhesion velocity is correlated with unique changes in the passivating layer thickness, thickness uniformity, crystallinity and composition resulting from exposure to high humidity. These results speak to particle surface treatments to improve the cold spray process.

ACTA Vol. 197, 15 Sept. 2020, P40-53

A method to eliminate hot cracking phenomena for aluminium alloys in Laser Beam Melting (LBM) is presented in this paper, focused here on the 6061 alloy. 6061 is a precipitation-hardened aluminium alloy, containing magnesium and silicon as its major alloying elements. This alloy, commonly used in the aeronautic and automotive industries, thanks to its excellent weight to strength ratio and high thermal conductivity, is particularly prone to hot cracking, in particular during LBM processing. The solution to remove cracks proposed in the present paper is to induce grain refinement to avoid the development of large columnar structures. To this end, various quantities of Yttrium Stabilized Zirconia (YSZ) are added to an Al6061 base powder using a dry mixing (TurbulaⓇ) procedure. Experiments highlight a grain refinement effect depending on the added YSZ quantity. From 1 vol% on, SEM and EBSD images reveal an equiaxed-columnar bimodal grain microstructure. Results show that the addition of 2 vol% YSZ allows to fully avoid cracks due to a continuous equiaxed band at melt pool boudaries. Additionally, TEM and DRX investigations provide new insights into the becoming of added particles along the printing process. The experimental results are then discussed on the basis of a number of existing solidification models, with a focus on the necessary conditions for the establishment of an equiaxed solidification regime.

ACTA Vol. 197, 15 Sept. 2020, P54-68

Molecular dynamics simulations are performed to investigate the impact of a coherent Σ3 (111) twin boundary on the plastic deformation behavior of Cu nanopillars. Our work reveals that the mechanical response of pillars with and without the twin boundary is decisively driven by the characteristics of initial dislocation sources. In the condition of comparably large pillar size and abundant initial mobile dislocations, overall yield and flow stresses are controlled by the longest, available mobile dislocation. An inverse correlation of the yield and flow stresses with the length of the longest dislocation is established and compared to experimental data. The experimentally reported subtle differences in yield and flow stresses between pillars with and without the twin boundary are likely related to the maximum lengths of the mobile dislocations. In the condition of comparably small pillar size, for which a reduction of mobile dislocations during heat treatment and mechanical loading occurs, the mechanical response of pillars with and without the twin boundary can be clearly distinguished. Dislocation starvation during deformation is more pronounced in pillars without the twin boundary than in pillars with the twin boundary because the twin boundary acts as a pinning surface for the dislocation network.

ACTA Vol. 197, 15 Sept. 2020, P69-80

We investigated the flow behavior of γ/γʹ-strengthened Co-12Ti and Co-12Ti-4Mo (at.%) alloys at room and elevated temperatures (up to 900°C) by electron microscopy and density functional theory. The Mo-added alloy exhibited an enhanced compressive yield strength and strain hardening behavior as compared to the reference binary alloy. This behavior could be attributed to a ~25% larger γʹ volume fraction and ~7% higher planar fault energies in Co-12Ti-4Mo. Using electron channeling contrast imaging, we observed interrupted slip bands in the Co-12Ti-4Mo alloy deformed to a strain of 6%, which led to enhanced strain hardening, in contrast to extended slip bands along {111} planes in the Co-12Ti alloy. Interrupted slip band formation in Co-12Ti-4Mo could be explained by rapid exhaustion of dislocation sources and a higher energy barrier required to cut the γʹ precipitates. These effects are due to a reduced γ channel width and substantial hardening effect of γʹ-Co3(Ti,Mo) in the ternary alloy as well as due to the large shear modulus difference between γʹ and γ.

ACTA Vol. 197, 15 Sept. 2020, P91-96

The substitutional solute atom induced local lattice distortion (LLD) in dilute metal solid solution was believed to be uniform because the solute atom was supposed to occupy the high symmetry lattice site without breaking the point group symmetry of the crystal lattice. Contrary to this conventional picture, we report in this paper that substitutional Mo atom in Ti-Mo solid solution occupies an off-center position instead of the high symmetry lattice site and leads to highly non-uniform LLD, as evidenced by our first principles calculations. The physics underlying the off-center occupation and non-uniform LLD are shown to be the Jahn-Teller splitting of the degenerated d states of Mo atom. With which, the solid-solutions suffering from non-uniform LLD are predicted. The non-uniform LLD challenges the application of classical solid solution hardening model based on uniform LLD and spherical stress tensor assumption to this kind of solid solutions. This work also questions the traditional view that elementary substitutional solute atoms in metal solid solutions should not induce anelastic relaxation and internal friction.

ACTA Vol. 197, 15 Sept. 2020, P97-107

Plasticity in hexagonal close-packed zirconium is mainly controlled by the glide of dislocations with 1/3〈1-210〉Burgers vectors. As these dislocations cannot accommodate deformation in the [0001] direction, twinning or glide of 〈c+a〉dislocations, i.e. dislocations with 1/3〈1-213〉 Burgers vector, have to be activated. We have performed in situ straining experiments in a transmission electron microscope to study the glide of〈c+a〉dislocations in two different zirconium samples, pure zirconium and Zircaloy-4, at room temperature. These experiments show that 〈c+a〉 dislocations exclusively glide in first-order pyramidal planes with cross-slip being activated. A much stronger lattice friction is opposing the glide of 〈c+a〉 dislocations when their orientation corresponds to the〈a〉direction defined by the intersection of their glide plane with the basal plane. This results in long dislocations straightened along〈a〉which glide either viscously or jerkily. This〈a〉direction governs the motion of segments with other orientations, whose shape is merely driven by the minimization of the line tension. The friction due to solute atoms is also discussed.

ACTA Vol. 197, 15 Sept. 2020, P123-136

Strain partitioning and localization were investigated in a high-Mn steel (17.1 wt.% Mn) during tensile testing by a correlative probing approach including in-situ synchrotron X-ray diffraction, micro- digital image correlation (μ-DIC) and electron microscopy. By combining Warren's theory with the μ-DIC analysis, we monitored the formation of planar faults (stacking faults and mechanical twins) and correlated them with the local strain partitioning behavior within the microstructure. Starting with an initial microstructure of austenite (γ) and athermally formed ε- and α’-martensite, strain accumulates preferentially near the γ/ε interfaces during tensile straining. The local microscopic von Mises strain (εvM) maps obtained from μ-DIC probing show that these local strain gradients produce local strain peaks approximately twice as high as the imposed macroscopic engineering strain (ε), thus locally triggering formation of ε-martensite already at early yielding. The interior of the remaining austenite, without such interfacial strain peaks, remained nearly devoid of planar faults. The local strain-driven growth of the ε-domains occurs concomitantly with the α’-martensite formation. At intermediate macroscopic applied strains, austenite grain size is considerably reduced to a few nanometers and the associated γ/ε interfacial microscopic strain peaks increase in magnitude. This scenario favors twinning to emerge as a competing strain hardening mechanism at engineering strain levels from ε = 0.075 onwards. At large tensile strains, the γ → ε → α’ transformation rates tend to cease making both twinning and SFs formation to operate as the main strain hardening mechanisms. The findings shed light on the transformation micro-mechanisms in multiphase Mn-TRIP steels by revealing how strain localization among the constituents can directly influence the kinetics of the competing strain hardening mechanisms.

ACTA Vol. 197, 15 Sept. 2020, P137-145

Nanoscale interdiffusion at the heterophase interfaces is the elementary process that controls solid-solid phase transformations and intermixing in multilayers. Here, we provide a direct experimental proof that the nanoscale multiphase interdiffusion is controlled by the interface mobility. We observed the anisotropic diffusion intermixing in Au–Fe bimetallic nanowhiskers, where the diffusion penetration depth of Fe into single crystalline Au nanowhisker across the incoherent Au–Fe interface was much greater than across its coherent counterpart. By applying a simple kinetic model to the results of diffusion measurements, we obtained the absolute values of mobilities of coherent and incoherent Fe-Au interfaces, and the Arrhenius parameters describing their temperature dependence. Atomic resolution scanning transmission electron microscopy confirmed that the lower mobility of the coherent interface is associated with the difficulties of the nucleation of interface disconnections. We proposed that the sluggish movement of the latter represents a kinetic “bottleneck” which determines the rate of intermixing. Our results indicate that the anisotropy of interface mobilities is a leading factor determining the anisotropic shape of precipitates formed in many heterogeneous solid-solid phase transformations.

ACTA Vol. 197, 15 Sept. 2020, P146-162

The effect of deformation twinning on the accessible slip and twin shear systems of a dislocated face-centered cubic structure and their critical stresses is studied. In particular, the plastic shear modes of critical matrix structure – single glide oriented Cu-8at.%Al alloy crystals deformed by room temperature tension up to the onset of deformation twinning - and the plastic shear modes of bimodal twin/matrix layered structure – subsequently twinned Cu-8at.%Al crystals – were examined. It was found that all twin and slip systems of the matrix structure may operate independently and their critical stresses are dispersed by about fifteen percent around the mean value. However, not all of the accessible slip and twin systems of the twin/matrix structure may operate independently and their critical stresses may differ by a factor of well over four. This large discrepancy of the critical stresses is responsible for giant yield stress anisotropy of the twin/matrix layered structure; the maximal and minimal yield stresses may differ even by one order of a magnitude. The twin/matrix layered structure reveals also very strong asymmetry of the tension/compression yield stress. It is suggested, that the giant anisotropy and very strong asymmetry of the yield stress have the same physical origin, i.e. the internal stress field associated with extended configurations of cube dislocations located within a twin lamellae - the deformation twinning induced effect of cube dislocation stress. It is concluded, that the cube dislocation stress effect seems greatly responsible for plasticity and strengthening of mechanically twinned face-centered cubic structures.

ACTA Vol. 197, 15 Sept. 2020, P172-183

A spinodal decomposition is often carried out in the austenite-ferrite duplex stainless steel Fe20Cr9Ni during long-term service at a temperature in the range from 280 to 320°C, resulting in a decrease of pitting corrosion resistance. Fe-rich α phase rather than G-phase has been suggested as the major reason for the deterioration in pitting corrosion resistance of the thermally-aged steel. Here, we found that ∼76.8% of the decline in pitting resistance for the duplex stainless steel Fe20Cr9Ni was attributed to G-phase, and ∼23.2% to Fe-rich α phase after the spinodal decomposition. In this study, a suitable thermal aging treatment was introduced to obtain a larger size of the G-phase and to study the role of the phase in the corrosion process. Through immersing thermally-aged TEM specimen treated at 475°C for 3000 h in NaCl solution, the preferential position of corrosion pits formed in the ferrite was obtained. The composition changes and strain field distribution around the G-phase were analyzed by TEM-EDS, 3DAPT and GPA techniques. We further found that, although the concentration difference of Cr element between α and α’ phases was as high as 60 at.%, corrosion pits were initiated at the interface between the G-phase and the ferrite matrix rather than in the Fe-rich α phase, indicating that the Cr-depleted theory could not explain the aforesaid phenomenon. The strain energy at the interface between the G-phase and the ferrite matrix was found to be the largest. The atoms at the interface have higher energy than in the intracrystalline, and thus easily react with Cl− ions in the solution to form pits finally.

ACTA Vol. 197, 15 Sept. 2020, P184-197

This work encompasses an in-depth transmission electron microscopy and atom probe tomography study of Ti-stabilized austenitic steel irradiated with Fe-ions. The focus is on radiation induced segregation and precipitation, and in particular on how Ti and TiC affect these processes. A 15-15Ti steel (grade: DIN 1.4970) in two thermo-mechanical states (cold-worked and aged) was irradiated at different temperatures up to a dose of 40 dpa. At low irradiation temperatures, the cold-worked and aged materials evolved to a similar microstructure dominated by small Si and Ni clusters, corresponding to segregation to small point defect clusters. TiC precipitates, initially present in the aged material, were found to be unstable under these irradiation conditions. Elevated irradiation temperatures resulted in the nucleation of nanometer sized Cr enriched TiC precipitates surrounded by Si and Ni enriched shells. In addition, nanometer sized Ti- and Mn-enriched G-phase (M6Ni16Si7) precipitates formed, often attached to TiC precipitates. Post irradiation, larger number densities of TiC were observed in the cold-worked material compared to the aged material. This was correlated with a lower volume fraction of G-phase. The findings suggest that at elevated irradiation temperatures, the precipitate-matrix interface is an important point defect sink and contributes to the improved radiation resistance of this material. The study is a first of its kind on stabilized steel and demonstrates the significance of the small Ti addition to the evolution of the microstructure under irradiation.

ACTA Vol. 197, 15 Sept. 2020, P198-211

Anomalous eutectic formation in undercooled Ni–Sn alloys was investigated by in situ X-ray diffraction and ex situ remelting and annealing experiments. Dynamic recrystallization and partial remelting of primary solids followed by repeated nucleation and growth of eutectic grains in the mushy zone were revealed by time-resolved X-ray diffraction. Ex situ experiments demonstrated that partial remelting of near-equilibrium solidified alloys of eutectic or near-eutectic composition can convert regular lamellar eutectic into anomalous eutectic, whereas high-temperature annealing of splat-quenched alloys of similar composition can convert eutectic or two-phase dendrites into anomalous eutectic. It is concluded that compared to ripening in solid-states, partial remelting of eutectic or two-phase dendrites in a mushy zone provides a more realistic mechanism for anomalous eutectic formation in undercooled solidification of Ni–Sn eutectic alloys.

ACTA Vol. 197, 15 Sept. 2020, P212-223

A very broad distribution of microstructural length scales spanning few nm- to the μm-scale has proven effective to achieve exceptional materials properties. Here, we fabricate a Cu/Nb two-phase composite made of a hierarchically layered structure by modifying the conventional accumulative roll bonding (ARB) technique, where fresh Nb sheets are inserted and bonded during a repeated stacking and rolling process. This barcode-like multilayer with a designed hierarchical length scale distribution possesses densely distributed phase boundaries and rich interfacial structures. The composite demonstrates similar superconductivity characteristics as pure Nb, but is 3 × stronger, has theoretically better oxidation resistance, and retains considerable ductility. Under the helium irradiation environment, the unique interfacial structures featuring chemical intermixing zones (3-dimensional) are more immune to the formation of large helium clusters than atomically sharp interfaces (2-dimensional), screening them from radiation damage and improving their long-term mechanical integrity. This work signifies an effective strategy of constructing hierarchical laminates to achieve high-performance materials, which holds promise in fusion and fission energy applications.

ACTA Vol. 197, 15 Sept. 2020, P253-268

We tackle the role of austenite in multiphase steels on hydrogen diffusion systematically for the first time, considering a range of factors such as morphology, interface kinetics and the additional effect of point traps using both experiments and modelling. This follows the findings from part I where we showed that austenite cannot be parametrised and modelled as point traps under the assumption of local equilibrium, unlike grain boundaries and dislocations. To solve this, we introduce a 2D hydrogen diffusion model accounting for the difference in diffusivities and solubilities between the phases. We first revisit the as-quenched martensite permeation results from part I and show that the extremely low H diffusivity there can be partly explained with the new description of austenite but is partly likely due to quench vacancies. We then also look at the H absorption and desorption rates in a duplex steel as a case study using a combination of simulations and experiments. The rates are shown to depend heavily on austenite morphology and the kinetics of H transition from ferrite to austenite and that an energy barrier is likely associated to this transition. We show that H diffusion through the ferrite matrix and austenite islands proceeds at similar rates and the assumption of negligible concentration gradients in ferrite occasionally applied in the literature is a poor approximation. This approach is also applicable to other austenite-containing steels as well as other multiphase alloys.

ACTA Vol. 197, 15 Sept. 2020, P269-282

When Ti-6Al-4V is processed by laser powder bed fusion (LPBF), a material with a martensitic microstructure is obtained. Moreover, the presence of internal stresses, an outer surface with relatively high surface roughness and the presence of remnant porosity all influence the fatigue life of high cyclically loaded components. The majority of investigations on LPBF produced Ti-6Al-4V have focused on a fatigue life method providing valuable, albeit limited, insight into fatigue failure mechanisms. Near-threshold fatigue crack growth rates are vital for describing fatigue crack initiation mechanisms and how these are influenced by residual stress, a martensitic microstructure and build orientation. This study investigates near-threshold fatigue crack growth rates of LPBF produced Ti-6Al-4V. The study makes use of full-size compact tension specimens for fatigue crack growth rate investigations, the contour method for residual stress measurement, and scanning electron microscopy with electron backscatter diffraction to consider both morphological and crystallographic texture. Results show anisotropic near-threshold fatigue crack growth rates that are dependant on residual stress levels and load-ratios. Fracture is predominantly governed by transgranular quasi-cleavage mechanisms, and the fracture path is directed by the columnar prior beta-grain structure resulting in orientation-dependant crack closure effects. Residual stresses result in crack opening that causes a shift of near-threshold fatigue crack growth rates. An intrinsic ΔKth of ~1.6 ± 0.2 MPa√m and critical Kmax of ~ 3 MPa√m is measured that is independent of the stress state but dependant on orientation. It is shown that this anisotropy is linked to morphological texture and to a lesser extent the crystallographic texture of LBPF produced Ti-6Al-4V.

ACTA Vol. 197, 15 Sept. 2020, P283-299

Many experimental and first principles studies on precipitation hardening alloys show that segregation of elemental species to the matrix-precipitate interphase boundary (IB) reduces the boundary’s energy. This segregation mechanism can thermally stabilize the microstructure against precipitate coarsening processes and allow for higher operating temperatures in structural applications. In this paper, we develop a phase-field modeling framework to describe IB solute segregation in ternary alloys. The interfacial thermodynamics is effectively described by defining an IB phase with a characteristic free energy-concentration dependence. Equilibrium for the IB phase is established via the parallel tangent plane construction, analogous to classical treatments for segregation to free surfaces and grain boundaries. Analytic steady-steady solutions elucidating the dependence of IB properties on bulk phase composition, temperature and model parameters are derived for a one-dimensional system. Analytic relations for the classical thermodynamic quantities–IB energy and relative solute excess–are derived and the Gibbs adsorption equation is shown to hold; therefore, predictions of the model can be compared with experiments and atomistic simulations. An application of the model is demonstrated for Zn segregation to Mg/Mg2Sn using representative IB parameters. A two-particle coarsening simulation of IB segregation is performed: the result demonstrates enhanced coarsening resistance of the ternary alloy relative to the binary alloy.

ACTA Vol. 197, 15 Sept. 2020, P300-308

In the present work, the elastic behavior of a metastable β-Ti alloy, Timetal-18, is studied in the β-quenched condition using in-situ far-field (ff) and near-field (nf) high energy synchrotron X-ray diffraction microscopy (HEDM) techniques and full-field crystal elasticity simulation. HEDM enables assessment of the 3D microstructure as well as the complete (6 components) elastic strain tensor and crystallographic orientation of each grain in the gauge volume of a polycrystalline aggregate. Using this elastic strain and orientation data from ~100 grains, a straightforward strategy to obtain the single crystal elastic constants (SEC) is demonstrated. The elastic moduli thus obtained are (in GPa): C₁₁ = 118 ± 5, C₁₂ = 79 ± 3, C₄₄ = 39 ± 4, with a Zener anisotropy ratio (A) of 2.0 ± 0.4. The nf-HEDM 3D microstructure was used to instantiate a virtual microstructure, as input into the parallelized code, Micromechanical Analysis of Stress-strain Inhomogeneities with fast Fourier transform (MASSIF), in order to simulate the grain level constitutive response. The predicted evolutions of the elastic strain tensor components are shown to be in good agreement with the measured values. However, grain-by-grain comparisons emphasize the strong effect of elastic anisotropy, suggesting it may be even higher than A = 2. The accuracy of the approach and implications for modeling the grain-level constitutive response in the plastic regime are discussed.

ACTA Vol. 197, 15 Sept. 2020, P330-340

Conductive and yet strong copper alloys are essential materials in highly mechanically loaded electrical devices. We demonstrate a novel in-situ synthesis approach via laser metal deposition (LMD) in a lean copper alloy, Cu–3.4Cr–0.6Nb (at%). Strengthening in the lean alloy comes from chromium nano-scale precipitates formed in-situ (4 nm diameter; number density 8 × 10²³ m−3) and from Laves phase particles (< 1 µm diameter; 2.2 vol%), dispersed across the microstructure. This dual dispersion, in a nearly pure copper matrix, is achieved through a suited combination of chromium alloying and cooling rate during LMD synthesis. The as-synthesized alloy has a conductivity of 68% IACS (International Annealed Copper Standard) and a Vickers hardness of 146, at room temperature. The latter is 11% above the value reported for the strongest lean reference ternary alloy Cu–8Cr–4Nb (at%). The in-situ synthesis approach averts any heat treatment step, which has been an essential step previously in conventional manufacturing, for realizing the property combination in lean Cu–Cr based system.