孿生的織構(gòu)調(diào)整及屈服行為演變(重慶大學(xué) 材料科學(xué)與工程學(xué)院，重慶 400030)
摘 要: 研究擠壓態(tài)鎂合金沿?cái)D壓方向預(yù)壓縮對(duì)隨后沿ED方向拉伸以及垂直于ED方向壓縮屈服行為的影響。結(jié)果表明：在所研究的1%~9%壓縮預(yù)變形范圍內(nèi)，不同預(yù)變形量對(duì)隨后沿ED方向拉伸的屈服影響幾乎一樣，都能使沿?cái)D壓方向拉伸屈服強(qiáng)度下降到約120 MPa，這幾乎與沿?cái)D壓方向壓縮屈服強(qiáng)度122 MPa一致；沿ED方向預(yù)壓縮將導(dǎo)致垂直于ED方向壓縮屈服強(qiáng)度顯著增加， 且不同預(yù)變形量對(duì)隨后沿垂直于ED方向壓縮的屈服行為影響幾乎一致。造成不同施載方向屈服行為不一樣的原因是不同施載方向?qū)\生變體的最大施密特因子值不同。最大施密特因子值越大，孿生啟動(dòng)時(shí)的臨界剪切應(yīng)力越小，屈服強(qiáng)度也就越低。
關(guān)鍵字: 鎂合金；孿生；織構(gòu)；施密特因子
twinning of magnesium alloy（College of Materials Science and Engineering, Chongqing University, Chongqing 400030, China）
Abstract:The effects of compressive pre-deformation on subsequent tension along extrusion direction (ED) and compression perpendicular to ED were investigated in an extruded AZ31 Mg alloy. The results show that the subsequent tensile yield stress decreases to about 120 MPa irrespective of the prestrain from 1% to 9%. The tensile yield stresses of about 120 MPa for the samples subjected to pre-compression are nearly equal to that of compression along ED (about 122 MPa) for the sample without any prestrain. However, the pre-compression along ED leads to an obvious increase in the yield stress for subsequent compression perpendicular to ED. Different prestrains exhibit similar effects on the yielding behavior during subsequent compression perpendicular to ED. Because of the difference in the highest Schmid factors for twinning, the samples exhibit different yielding behaviors under different strain paths. The critical resolved shear stress (CRSS) decreases with the increase of the highest Schmid factor for twinning.
Key words: magnesium alloy; twinning; texture; Schmid factor
