形核剂的添加方式对选区激光熔化成形含锆Al-Cu-Mg合金显微组织与力学性能的影响  

Effect of Adding Methods of Nucleating Agent on Microstructure and Mechanical Properties of Zr Modified Al-Cu-Mg Alloys Prepared by Selective Laser Melting

作　　者：王凯冬 刘允中[1] 詹强坤 黄斌 WANG Kaidong;LIU Yunzhong;ZHAN Qiangkun;HUANG Bin(National Engineering Research Center of Near-Net-Shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学国家金属材料近净成形工程技术研究中心,广州510640

出　　处：《金属学报》2022年第10期1281-1291,共11页Acta Metallurgica Sinica

基　　金：广东省重点领域研发计划项目No.2019B090907001;广东省重大科技专项项目No.2014B010129002。

摘　　要：采用选区激光熔化技术制备了含锆Al-Cu-Mg合金,研究了不同方式添加Al_(3)Zr形核剂对试样显微组织和力学性能的影响。结果表明,直接添加Al_(3)Zr和原位生成Al_(3)Zr均能抑制该合金试样的热裂纹,当激光能量密度为370 J/mm3时,试样的平均晶粒尺寸分别由15.69μm细化至1.88和1.28μm。原位生成Al_(3)Zr提供的形核剂均为亚稳态Al_(3)Zr立方相(L1_(2)-Al_(3)Zr),形核能力高于直接添加Al_(3)Zr获得的Al_(3)Zr颗粒和L1_(2)-Al_(3)Zr形核剂。原位生成Al_(3)Zr的Al-Cu-Mg合金综合力学性能更为优异,T6热处理态试样抗拉强度达(485±10)MPa,伸长率比直接添加Al_(3)Zr的合金高出30%。原位生成Al_(3)Zr几乎无需通过高的激光能量密度增强Marangoni对流来实现晶粒细化剂的分散,可使Al-Cu-Mg合金适用于较高速率成形。Selective laser melting(SLM)technology is gaining increasing attention in the field of additive manufacturing.Al-Cu-Mg alloy parts manufactured using SLM technology exhibit significant advantages in lightweight design and the integrated formation of complex structural parts in the aerospace field.However,because of their wide freezing ranges,Al-Cu-Mg alloys have a high cracking tendency at a high cooling rate.SLM technology was used to prepare Zr-modified Al-Cu-Mg alloys in this study.Al_(3)Zr particles were synthesized to directly add to Al-Cu-Mg alloy powders,and ZrH2 particles were chosen to form Al_(3)Zr in-situ during SLM processes.The differences between the effects of adding Al_(3)Zr particles directly and forming Al_(3)Zr in-situ on the microstructures and the mechanical properties of SLMed Al-Cu-Mg alloys were analyzed.The results show that the common hot tearing in as-built Al-Cu-Mg alloys all disappear due to the addition of Al_(3)Zr nucleating agent and the in-situ formed Al_(3)Zr is more conducive to refining grains and improving the plasticity and the processing efficiency of SLMed Al-Cu-Mg alloys.When the laser energy density is 370 J/mm^(3),the grain size of the samples containing Al_(3)Zr and in-situ formed Al_(3)Zr particles are 1.88 and 1.28μm,respectively.L1_(2)-Al_(3)Zr and undissolved or unmelted Al_(3)Zr particles are the nucleation particles generated by initial Al_(3)Zr particles;whereas,they are all metastable Al_(3)Zr(L1_(2)-Al_(3)Zr)synthesized in-situ.L1_(2)-Al_(3)Zr has a better nucleation ability than initial Al_(3)Zr particles.The ultimate strength of the heat-treated samples with initial Al_(3)Zr particles or in-situ formed Al_(3)Zr can reach(493±2)or(485±10)MPa,respectively.The elongation of the samples with the in-situ formed Al_(3)Zr is more than 30%higher than that of the samples containing Al_(3)Zr particles.SLMed Al-Cu-Mg alloys with in-situ formed Al_(3)Zr are more suitable for medium-high-speed processes because strong Marangoni flow aroused by high laser energy density

关 键 词：选区激光熔化 AL-CU-MG合金 Al_(3)Zr 显微组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]