本文研究了不同Sm含量对挤压态Mg-6Al-2Sr合金的强化机理,采用金相实验、X射线衍射、扫描电镜和透射电镜对显微组织进行观察,并通过EBSD分析了Sm含量对合金显微组织的影响.本文主要是对不同Sm含量的Mg-6Al-2Sr铸态合金进行挤压实验.结果表明:随着Sm含量的增加,生成的Al2Sm相在挤压的作用下破碎,并且沿挤压方向在晶界处均匀弥散,阻碍晶粒长大;继续不断增加Sm,使得在晶界处Al2Sm相增多聚集,反而对合金力学性能产生不利影响;当Sm含量为1.5 wt%时,合金的平均晶粒尺寸最细小,其抗拉强度、屈服强度和伸长率达到297.9 MPa、257.8 MPa和21.3%,硬度达到HV78.9,较Sm含量为0 wt%的合金,抗拉强度提升了15.6%,屈服强度提升了34.6%,伸长率提升了34.8%.
In this paper,the strengthening mechanism of different Sm content on extruded Mg-6Al-2Sr alloy was studied.The microstructure was observed by metallographic experiment,X-ray diffraction,scanning electron microscopy and transmission electron microscopy,and the effect of Sm content on the microstructure of the alloy was analyzed by EBSD.The main experiment in this paper is the extrusion experiment of Mg-6Al-2Sr cast alloy with different Sm content.The results show that with the increase of Sm content,the generated Al2Sm phase is broken under the action of extrusion,and uniformly dispersed at the grain boundary along the extrusion direction,which hinders the grain growth.However,with the increase of Sm content,the Al2Sm phase increases and aggregates at the grain boundary,which has an adverse effect on the mechanical properties of the alloy.When the Sm content is 1.5 wt%,the average grain size of the alloy is the finest,and its tensile strength,yield strength and elongation reach 297.9 MPa,257.8 MPa and 21.3%,respectively.The hardness reaches HV78.9,which is 15.6%higher than that of the alloy with 0 wt%Sm content.The yield strength increased by 34.6%and the elongation increased by 34.8%.