低密度镁锂合金性能强化与精密成形技术

Performance Enhancement and Precision Forming Technology of Lowdensity Mg-Li Alloy

针对轻质高强和近成形复杂结构的技术要求,提出一种基于低密度镁锂合金薄壁筒形件的等温超塑性双向挤压近净成形方法,研究了铸态成形性能、铸态和轧制态在不同温度下的力学性能变化规律。研究结果表明,铸态下延伸率约12%,抗拉强度约145 MPa,轧制态下延伸率变化不大,但抗拉强度提升到180 MPa以上。采用本论文方法镁锂合金的延伸率和抗拉强度显著提高,分别达到21%和216 MPa,表明高温大变形过程中,实现了晶粒细化,大量增强相弥散在晶粒内部,起到性能强化作用,成功实现其性能强化和复杂结构件的精密成形。

tIn order to meet the requirements of light weight,high strength and near net forming of a complicated aerospace component,an isothermal superplastic forward and backward extrusion near net forming method based on thin-walled component of low-density Mg-Li alloy was proposed.The formability of as-cast and the mechanical properties of as-cast and as-rolled at different temperatures were studied.The results show that the elongation of ascast is about 12%,and the tensile strength is about 145 MPa.The elongation of as-rolled has little change,but the tensile strength increases to more than 180 MPa.The elongation and tensile strength obtained by this method are significantly improved,reaching 21%and 216 MPa,respectively,which indicates that the grain refinement is realized in the process of high temperature and large deformation.While many reinforcement phases are dispersed in the grain,which plays the role of performance enhancement.The performance enhancement and precision forming of complicated structural parts are successful achieved.