摘要
采用激光增材制造工艺对铝合金复杂构件进行打印制备可以在满足材料-结构轻量化的同时提高其承载性能。7075铝合金的凝固区间较宽,在LPBF快速熔凝过程中极易引发裂纹缺陷,严重限制该类合金的应用范围。采用LPBF工艺对7075铝合金进行了制备成形,同时对不同工艺参数下7075铝合金的成形特性、凝固结晶行为及组织性能进行分析,研究熔化方式对其组织和性能的影响。在高扫描速度区间(800~2 400 mm/s)时,合金内部存在较多的裂纹及气孔缺陷,显微组织为粗大的柱状晶组织;而当扫描速度为400 mm/s时,样品中的缺陷消失。随着扫描速度的降低,其熔化模式由热传导模式逐渐变为匙孔模式,在该模式下晶粒尺寸达到显著细化,力学性能获得了较大提高,抗拉强度和延伸率分别达到329 MPa和11.2%。
The fabrication of aluminum alloy complex components by using laser additive manufacturing process can satisfy the material-structure lightweight and improve the bearing performance.The solidification range of 7075aluminum alloy is so large that the crack defects are easily caused due to the rapid solidification process of LPBF.And it is seriously limits the application of this alloy.In this paper,the LPBF process was applied to print the 7075aluminum alloy,and the forming characteristics,solidification and crystallization behaviors,microstructure and properties were analyzed.The influence of melting mode on the microstructure and properties was also studied.In the high scanning speed range(800~2400mm/s),there are many cracks and porosity defects existed inside the alloy,and the microstructure is mainly coarse columnar crystals.When the scanning speed is 400mm/s,the defects are disappeared.With the decrease of scanning speed,the melting mode gradually changed from heat conduction mode to keyhole mode,and the grain size was significantly refined.The mechanical properties of printed parts were greatly improved,and the tensile strength and elongation were 329MPa and 11.2%,respectively.
作者
胡士齐
Hu Shiqi(College of Mechanical and Electrical Engineering,Henan Vocational University of Science and Technology,Zhoukou453003,Henan,China)
出处
《应用激光》
CSCD
北大核心
2024年第4期7-14,共8页
Applied Laser
关键词
7075铝合金
激光增材制造
熔化模式
结晶行为
组织性能
7075aluminum alloy
laser additive manufacturing
melt mode
crystallization behavior
microstructure and properties
