激光选区熔化成形高强铝合金晶粒细化抑制裂纹研究现状  

Research status of crack inhibition via grain refinement of high-strength aluminum alloys fabricated by selective laser melting

作　　者：刘小辉[1] 刘允中[1] LIU Xiaohui;LIU Yunzhong(National Engineering Research Center of Near-net-shape Forming for Metallic Materials,South China University of Technology,Guangzhou 510641,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510641

出　　处：《材料工程》2022年第8期1-16,共16页Journal of Materials Engineering

基　　金：广东省重点领域研发计划项目(2019B090907001);广东省科技计划项目(2014B010129002)。

摘　　要：高强铝合金(2×××,7×××等)因具有比强度高、加工性好等优点而被航空航天、汽车等领域广泛应用。随着大推重比飞行器设计及汽车轻量化技术的发展,轻质结构材料的需求日益增加,同时零部件也面临着“薄壁化、中空化、复合化”的发展趋势,高强铝合金的传统加工方法越来越难以满足要求。近年来,激光选区熔化成形(selective laser melting,SLM)作为一种常见的金属增材制造技术(additive manufacturing,AM)在复杂零部件成形领域受到关注,有望成为进一步拓宽高强铝合金应用领域的新兴技术。然而,SLM成形高强铝合金因易产生周期性热裂纹和粗大柱状晶不良组织等问题而发展缓慢,晶粒细化是克服增材制造高强铝合金这一固有热裂问题的关键所在。本文综述了近年来SLM成形高强铝合金显微组织和力学性能调控等方面的研究进展,归纳了不同体系合金的力学性能,重点阐述了抑制SLM成形高强铝合金中热裂纹形成的主要策略,包括SLM工艺参数优化以及通过微合金化或添加纳米颗粒细化晶粒等方法。指出当前研究存在的主要问题是合金成分的改变对材料综合性能以及热处理制度的影响规律尚不清晰等,并展望了未来的发展趋势,如SLM成形新型高强铝合金成分设计与综合性能评价、利用后处理工艺等手段进一步提升合金综合性能以及专用晶粒细化剂的设计与细化机制探究等。High-strength aluminum alloys(2×××and 7×××,etc.)are widely used in aerospace,automobile and other fields because of their high specific strength and good machinability.With the development of high thrust-weight ratio engine and automobile lightweight technology,the demand for lightweight structural materials is increasing.Meanwhile,parts also present the“thin-walled,hollow and composite”tendency gradually,and the traditional processing methods of high-strength aluminum alloy are increasingly difficult to meet the requirements.As a common metal additive manufacturing(AM)technology,selective laser melting(SLM)is a great potential manufacturing technology for complex parts.SLM is expected to become an emerging technology to expand the application of high-strength aluminum alloys.However,due to their poor casting and welding properties,high-strength aluminum alloys easily produce the periodic hot cracks and coarse columnar grains during SLM,leading to unsatisfactory mechanical properties.Grain refinement is the key to overcome the inherent hot-tearing crack of SLMed high-strength aluminum alloys.The research progress in microstructure and mechanical property control of SLMed high-strength aluminum alloys in recent years was reviewed.The mechanical properties of alloys with different compositions were summarized.Importantly,the main strategies to suppress hot-crack formation in SLMed high-strength aluminum alloys were highlighted,including optimization of SLM process parameters and grain refinement by microalloying or addition of nanoparticles.It was pointed out that the main issue of SLMed high-strength aluminum alloys was the change of alloy composition on the comprehensive properties and heat treatment process was still unclear.The development trends were forecasted,such as designing new high-strength aluminum alloys and evaluating their comprehensive performances,using post-treatment process and other means to further improve the comprehensive performances of the alloys,and designing special grain refine

关 键 词：高强铝合金 激光选区熔化 晶粒细化 热裂纹 增材制造 

分 类 号：TG146.2[一般工业技术—材料科学与工程]