We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
A quantitative microplasticity-based approach to rationalize the poor strengthening response of polycrystalline Mg alloys
Summary
Researchers used microscale mechanical testing to investigate why tiny nanoprecipitates — added to magnesium alloys to strengthen them — often fail to improve strength as expected. They found that in grains oriented for easy slip, dislocations (defects that allow metals to deform) can cut through the nanoparticles rather than being blocked by them, causing localized softening rather than strengthening.
This work aims to understand the inefficiency of nanoprecipitates to strengthen a weakly textured, polycrystalline Mg-Gd-Y-Zr alloy. An experimental micromechanical approach consisting on micropillar compression combined with analytical electron microscopy is put in place to analyze the effect of nanoprecipitation on soft and hard basal slip and twinning in individual grains with different orientations. This study shows that, in grains that are favorably oriented for basal slip (“soft” basal slip), aging leads to extreme localization due to the ability of basal dislocations to shear the nanoparticles, resulting overall in the softening of basal systems. Additionally, in grains in which the c-axis is almost perpendicular to the compression axis, prismatic slip dominates deformation in the solid solution state and nanoprecipitation favors twinning due to the concomitant lattice solute depletion. Finally, in grains oriented with their c-axis making an angle of about 5–7° with respect to the compression axis, which deform mainly by “hard” basal slip, precipitation leads to the strengthening of basal systems in the absence of obvious localization. This work reveals that the poor hardening response of the polycrystalline alloy is related to the capability of basal dislocations to shear the nanoparticles, in the absence of Orowan looping events, and to the associated basal slip localization.
Sign in to start a discussion.
More Papers Like This
Effect of Heat Treatment on Microstructure and Microplasticity of Magnesium Alloys Containing Long-Period Stacking Ordered Structures
Researchers investigated how heat treatment affects the microstructure and microplasticity of magnesium alloys containing Zn, Y, Gd, Yb, and Zr, with approximately 15% long-period stacking-ordered nanostructured phase, measuring internal friction and elastic modulus amplitude dependences to assess deformation mechanisms.
Temperature-driven nanoscale brittle-to-ductile transition of the C15 CaAl2 Laves phase
Researchers used nanoscale mechanical testing to study how the metal alloy compound CaAl2 transitions from brittle to ductile behavior as temperature rises, a key property for designing stronger magnesium alloys. They identified a transition temperature range around 55% of the material's melting point, where increased dislocation movement — atomic-scale defect shifts — enables plastic deformation without cracking.
Unravelling dislocation networks in metals
Researchers developed a detailed model to measure and describe the network of tiny defects called dislocations inside metal materials, which affect how metals deform under stress. By linking dislocation density and segment length to mechanical test data, the model improves understanding of how metals behave during plastic deformation — the irreversible bending or shaping of metal.
Probing Microplasticity in Small-Scale FCC Crystals via Dynamic Mechanical Analysis
This study used dynamic mechanical analysis to study pre-yield dislocation activity — tiny structural movements — in small-scale face-centered cubic metal crystals. It is a materials science paper on nanoscale metal plasticity with no connection to environmental microplastics.
Low Amplitude Nonlinear Damping and Effective Modulus in Magnesium Alloys Containing Long-Period Stacking Ordered Structures
Despite its title referencing "microplasticity" (a materials science term for microscale deformation in metals), this paper studies the mechanical damping properties of magnesium alloys — not microplastic pollution. It examines elastic modulus and vibration damping in metal alloys at low temperatures, and is entirely unrelated to microplastics or environmental health.