Yang Jiandong, Wang Wuxiao, Zhang Min, Liu Jian, Qin Shaoyong
School of Material Science and Engineering, Xi'an University of Technology, Xi'an 710048, China.
Xi'an Aeronautical Polytechnic Institute, Xi'an 710089, China.
Materials (Basel). 2023 Oct 18;16(20):6747. doi: 10.3390/ma16206747.
The effects of Mn addition on the room temperature tensile strength and deformation mechanisms of as-cast Mg-8Al-1Nd-1.5Gd-Mn alloys ( = 0, 0.3, 0.5, 1.0 wt.%) are investigated in this paper. The results indicate that the addition of Mn contributes to the precipitation of Al-Mn-RE intermetallics and the refinement of -Mg matrices, thereby improving the tensile strength of the 1.0 Mn alloy at 190 MPa. The fracture mechanism of Mn-containing alloys transforms from a cleavage fracture to a ductile fracture as the Mn content increases from 0.3 to 1.0 wt.%. The presence of intermetallic particles in the dimples confirms the hindrance effect of AlMn (Nd,Gd) on dislocation slips. The novel technology of in-grain misorientation axes (IGMAs) is used to identify activated slip modes and deformation twins. It can be concluded that the activated pyramidal slip during tensile deformation significantly promotes the ductility of the 1.0 Mn alloy with an elongation rate of 9.8%. It is worth noting that reducing the coarse 101¯2 tensile twins and enhancing the proportion of 101¯1 compressive twins and 101¯1-101¯2 double twins contributes to maintaining the continuous plastic deformation of Mg alloy.
本文研究了添加锰（Mn，含量分别为0、0.3、0.5、1.0 wt.%）对铸态Mg-8Al-1Nd-1.5Gd-Mn合金室温拉伸强度及变形机制的影响。结果表明，添加锰有助于Al-Mn-RE金属间化合物的析出以及α-Mg基体的细化，从而使含1.0%Mn合金的拉伸强度提高至190 MPa。随着锰含量从0.3 wt.%增加到1.0 wt.%，含锰合金的断裂机制从解理断裂转变为韧性断裂。韧窝中金属间化合物颗粒的存在证实了AlMn（Nd，Gd）对位错滑移的阻碍作用。采用晶内取向错轴（IGMAs）新技术来识别激活的滑移模式和变形孪晶。可以得出结论，拉伸变形过程中激活的锥面<101¯2>滑移显著提高了含1.0%Mn合金的延展性，其伸长率为9.8%。值得注意的是，减少粗大的<101¯2>拉伸孪晶并提高<101¯1>压缩孪晶和<101¯1>-<101¯2>双孪晶的比例有助于维持镁合金的连续塑性变形。
