Nd对压铸AZ91D合金组织与性能的影响

传统压铸获得AZ91D和AZ91D-1.11Nd两种合金试样,采用光学金相显微镜、扫描电子显微镜和X射线衍射仪分析了压铸态微观组织和相组成,并测试了其拉伸力学性能、硬度、导热性能和流动性能。结果表明,在AZ91D合金中添加1.11%Nd后,压铸态晶粒有所细化,形成较多弥散分布的细小颗粒状Al2Nd和少量针状Al₁₁Nd₃,原有的半连续网状分布的β-Mg₁₇Al₁₂数量有所减少。压铸态AZ91D-1.11Nd合金呈现良好的综合性能,室温抗拉强度、伸长率和热导率分别为272 MPa、12.0%和69.5 W/(m·K),与AZ91D合金相比分别提高14%、100%和14%;同时呈现与AZ91D合金相当的优异铸造工艺性能,流动长度达到1161 mm。

Effect of Nd on Microstructure and Properties of Die Casting AZ91D Alloy

AZ91D and AZ91D-1.11ND alloy samples were obtained by traditional die casting method.The microstructure and phase constituents were analyzed by using optical metallographic microscope,scanning electron microscope and X-ray diffraction.Meanwhile,the tensile properties,hardness,thermal conductivity and fluidity were tested.The die cast alloy showed fine grains after adding 1.11%Nd into AZ91D alloy;and many dispersed fine granular Al2Nd and small amounts of acicular Al₁₁Nd₃ were formed,while the original semi-continuous reticulatedβ-Mg₁₇Al₁₂ decreased.The die cast AZ91D-1.11Nd alloy also exhibited good comprehensive properties,in which the tensile strength,elongation and thermal conductivity at room temperature reach 272 MPa,12.0%and 69.5 W/(m·K),respectively,with an increase of 14%,100%and 14%,respectively,compared with those of AZ91D alloy.At the same time,the alloy presented excellent casting properties comparable to AZ91D alloy,with fluid length up to 1161 mm.