无铅易切削铝合金挤压棒材的组织与性能研究

Research on microstructure and mechanical properties of lead-free and free-cutting aluminum alloy extruded bars

用锡、铋替代铅制备了2011和6026两种无铅易切削的铝合金挤压棒材,并利用光学显微镜、扫描电镜、拉伸试验机和车床等手段研究了这两种无铅易切削铝合金挤压棒材的显微组织、拉伸力学性能与切削加工性能。结果表明:2011铝合金挤压棒材的显微组织由α-Al、CuAl_(2)、Al_(7)Cu_(2)Fe和SnBi共晶相组成,6026铝合金挤压棒材的显微组织由α-Al、Mg_(2)Si、CuAl_(2)和SnBi共晶相组成。两种无铅易切削铝合金挤压棒材都具有良好的切削加工性能和拉伸力学性能。2011铝合金挤压棒材的抗拉强度为486.1 MPa,屈服强度为421.5 MPa,伸长率为10.4%;6026铝合金挤压棒材的抗拉强度为358.7 MPa,屈服强度为296.4 MPa,伸长率为13.8%。

The lead-free and free-cutting 2011 and 6026 aluminum alloy extruded bars were prepared by substituting Sn and Bi for Pb.The microstructure,mechanical properties and machinability of 2011 and 6026 aluminum alloy extruded bars were studied by means of optical microscope,scanning electron microscope,tensile testing machine and high-speed lathe.The results show that the microstructure of 2011 aluminum alloy extruded bar is composed ofα-Al,CuAl_(2),Al_(7)Cu_(2)Fe and Sn and Bi symbiosis phases.The microstructure of 6026 aluminum alloy extruded bar is composed ofα-Al,Mg_(2)Si,CuAl_(2)and Sn and Bi symbiosis phases.2011 and 6026aluminum alloy extruded bars have good machinability and tensile mechanical properties.The tensile strength of 2011 aluminum alloy extruded bar is 486.1 MPa,yield strength is 421.5 MPa and the elongation is 10.4%.The tensile strength of 6026 aluminum alloy extruded bar is 358.7 MPa,yield strength is 296.4 MPa and the elongation is 13.8%.