Effect of Precipitates in Mg−Sm Alloys on Their Deformation Behavior and Yield Asymmetry. Issue 4 (19th January 2022)

• Record Type: Journal Article
• Authors: Ou, Xiaoqin; Liu, Feiya; Tan, Chuan; Ren, Weijie; Xin, Renlong; Liu, Qing
• Is Part Of: Advanced engineering materials. Volume 24:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-19
• Subjects: aging precipitation -- crystal plasticity -- Mg−Sm alloys -- textures -- yield asymmetry; Materials -- Periodicals; 620.11
• DOI: 10.1002/adem.202101063
• Languages: English
• ISSNs: 1438-1656

Abstract

Abstract : The strengthening effect of precipitates in a Mg−0.4Sm (wt%) alloy on dislocation slip and extension twinning (ET) is evaluated by experimental work and viscoplastic self‐consistent (VPSC) modeling. Experimental results reveal that the extruded Mg−Sm alloy consists of rare‐earth texture (<−12−11> // ED) and extrusion texture (<−12−10> // ED) components. After aging precipitation, tensile yield stress is more effectively enhanced than compressive yield stress. Transmission electron microscopy (TEM) analysis confirms that the precipitates in the aged Mg−Sm alloy are of β′ with an orthorhombic crystal structure. The introduction of β′ precipitates in the compression sample stimulates a higher fraction of extension twins. VPSC modeling indicates that the critical‐resolved shear stresses (CRSS) for prismatic slip, pyramidal slip, and basal slip are increased by 75, 30, and 6 MPa, respectively, by aging precipitation, while the precipitation strengthening on ET is negligible. By preferentially hardening against prismatic slip, the compressive and tensile yield asymmetry are increased for the aged Mg−Sm alloy. Abstract : Due to the different precipitation strengthening effects on the various deformation modes and the rare‐earth (RE) texture in Mg−Sm alloy, the increment in tensile yield strength (YS) is much higher than that in compressive YS. As a consequence, the compressive and tensile yield asymmetry becomes worse, which is different from that normally reported in RE‐free Mg alloys.