Critical resolved shear stress of activated slips measured by micropillar compression tests for single-crystals of Cr-based Laves phases

Single-crystal micropillar compression tests were performed in this study to investigate the mechanical properties and deformation mechanisms of Cr-based Laves phases. The results showed that, the activated slip system in the C15-Cr2Nb was exclusively the basal slip {111}< 110 >, transiting from the pyramidal slip {11 (2) over bar2}<(11) over bar 23 > to the prismatic slips {10 (1) over bar0}< 0001 > and {11 (2) over bar0}< 1 (1) over bar 00 > in the C14-Cr2Ta with the increased inclination angle. The average compressive strength of the C15-Cr2Nb changed between 10.0 GPa and 11.7 GPa, and that of the C14-Cr2Ta ranged within 11.6-12.4 GPa. The compressive strength changed due to the evolutions of activated slip systems in both Laves phases. The critical resolved shear stress (CRSS) of the C15-Cr2Nb was estimated as 4.4-4.6 GPa, which was lower than 5.1-6.1 GPa in the C14-Cr2Ta, and the higher CRSS of the C14-Cr2Ta resulted from higher shear modulus. The mechanical properties and deformation mechanisms obtained were helpful for better understanding and designing the Cr-based Laves phase alloys.

Automated summary

Single-crystal micropillar compression tests were conducted to investigate the mechanical properties and deformation mechanisms of Cr-based Laves phases. Different activated slip systems were observed in the C15-Cr2Nb and C14-Cr2Ta, leading to variations in compressive strength. Additionally, the higher critical resolved shear stress in C14-Cr2Ta was attributed to its higher shear modulus.