T4热处理对不同钕含量AM60镁合金显微组织和力学性能的影响

Effect of T4 Heat Treatment on Microstructure and Mechanical Properties of AM60 Magnesium Alloys with Different Nd Contents

用真空电阻炉、在氩气保护下制备了不同钕含量的AM60合金,用箱式电阻炉对其进行了T4热处理;研究了两种状态合金显微组织和力学性能随钕元素含量的变化规律。结果表明:铸态合金的显微组织均主要由-αMg基体相、-βMg17Al12相和Al11Nd3相组成;T4热处理后,β-Mg17Al12相溶解到-αMg基体相中,合金晶粒明显细化,Al11Nd3相形貌上有较大的变化;随钕含量的增加,合金的抗拉强度、屈服强度和伸长率均先升后降,峰值时钕含量由铸态的0.9%降到T4态的0.3%,T4态的分别达239,138 MPa和8%,显微硬度峰值出现在0.6%Nd,为70.5 HV。

AM60 alloys with different Nd contents were prepared in vacuum resistance furnace under Ar atmosphere, and then T4 heat treatment was carried out in box-type resistance furnace. The change law of the microstructure and mechanical properties of two state alloys was studied. The results show that the microstructure of as-cast alloys mainly consisted of ^-Mg matrix phase, α-Mg17 Al12 phase and Alll Nd3 phase. After T4 heat treatment, the β-Mg17 Al12 phase decomposed and dissolved into the α-Mg matrix phase. The grain size of alloys was refined obviously and the morphology of Al11 Nd3 phase changed greatly. With the increase of Nd content, the tensile strength, yield strength and elongation increased first and then decreased. The peak values of the mechanical properties changed from 0.9%Nd in as-cast state to 0. 3%Nd in T4 state, which reached 239 MPa, 138 MPa and 8%, respectively. The microhardness of the 0. 6% Nd alloy reached 70. 5 HV.