双相镁锂合金正挤压有限元模拟与实验分析

Numerical simulation and experimental research on direct extrusion for dual-phase magnesium lithium alloy

以LZ92镁锂合金为研究对象,采用Deform-3D软件对其正挤压变形方式进行数值模拟。研究了不同挤压比(分别为10,20和30)对等效应力和等效应变的影响。结合正挤压变形的分析结果进行热挤压实验,对变形后的试样进行显微组织观察和力学性能测试。结果表明:随着挤压比的增大,试样的等效应变增大,均匀性增强,等效应变以0.5的增长速度线性增长,最大等效应变高达3;LZ92镁锂合金再结晶越充分,晶粒细化越明显,晶粒尺寸由45μm细化至约15μm。LZ92变形镁锂合金具有优异的力学性能,随着挤压比的增大,屈服强度、抗拉强度和变形量显著提升,抗拉强度逐渐增大至203.1 MPa,较铸态提高了76%,屈服强度以40 MPa的增长速度线性增长。

For magnesium lithium alloy LZ92,the deformation mode of direct extrusion was numerically simulated by Deform-3D finite element software,and the influences of different extrusion ratios of 10,20 and 30 on equivalent stress and equivalent strain were analyzed.According to the simulation analysis result of direct extrusion,the hot extrusion test was carried out to observe the microstructure and mechanical properties of the deformed samples. The results show that with the increase of extrusion ratio,the equivalent strain increases,and the sample homogeneity is enhanced. Therefore,the equivalent strain is in linear growth with a growth rate of 0. 5,and the maximum equivalent strain is up to 3. At the same time,the more sufficient the recrystallization of magnesium lithium alloy LZ92 is,the more obvious the grain refinement is,and the grain size is refined from 45 μm to 15 μm. LZ92 deformation magnesium lithium alloy has excellent mechanical properties. With the increase of extrusion ratio,the yield strength,tensile strength and deformation significantly increase. The tensile strength gradually increases to 203. 1 MPa which is 76% more than the cast state,and the yield strength grows linearly at a speed of 40 MPa.