Sm对AM60合金显微组织和力学性能的影响

Effect of Sm on Microstructure and Mechanical Properties of AM60 Magnesium Alloy

借助光学显微镜、扫描电镜、X射线衍射仪和DNS100电子万能试验机研究AM60合金中加入Sm后的显微组织和力学性能,并分析Sm对合金显微组织和力学性能的影响。结果表明,添加元素Sm可以细化镁合金的晶粒,改变β相的形态和大小,从连续或断续网状、长条状,变为卵石状或颗粒状均匀弥散分布在α-Mg基体上,显著改善合金的显微组织。Sm的加入可形成稳定性较高的颗粒状Al2Sm高温化合物相。随着Sm含量的增加,合金的抗拉伸强度和伸长率呈现先升后降的趋势,当Sm含量为1.0%(质量分数,下同)时抗拉伸强度和伸长率分别达到最大值210MPa和6.9%。室温下AM60合金的断口呈解理断裂,加入Sm变质后其断口形貌表现为准解理+局部韧性断裂特征。

Microstructures and mechanical properties of AM60 magnesium alloy with Sm addition were investigated through OM,SEM XRD and DNS100 electronic universal testing machines.The results show that the addition of Sm can refine grains,change the morphology and the size of β-Mg17A112 phase from continuous/discontinuous netlike or strip form to cobble or particulate form.The distribution also becomes homogeneous and dispersed,and obviously improves the microstructure.After Sm addition to the alloy,the dispersed,high-melting-point particles（mainly Al2Sm phase） are formed.With increasing of Sm content,the tensile strength and elongation of AM60 magnesium alloy increase first and then decrease.With addition of 1.0wt% Sm,the tensile strength and elongation of the alloy reach the maximum 210 MPa and 6.9%,respectively.The tensile fracture mechanism of AM60 magnesium alloy is changed from cleavage fracture to quasi-cleavage fracture with toughness characteristic.