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为克服传统等径角挤压反复多道次累积塑性变形带来多次装料、多次加载以及棒料机械加工等耗时问题,无损伤地制备均匀超细晶结构时效硬化型铝合金,提出旋转通道等径角平行挤压大塑性变形新工艺。该工艺在一个通道内设置多个剪切变形区,通过在两个等径角挤压通道之间设置旋转通道来改变圆棒料剪切方向和剪切角度,实现Bc加工路径,提高变形均匀性。采用正交试验法选取内角Φ、外角Ψ、升角γ、椭圆因子m、第2个通道中第1段直通道长度L_1作为因素,采用有限元模拟法对棒料在16组不同水平的模具中进行有限元挤压模拟。以等效应变、等效应力、损伤量以及变形均匀性系数作为指标值分析其对挤压过程的影响。模拟实验结果表明,良好的挤压通道内角Φ的合理范围为90°~120°,外角Ψ的合理范围为30°~40°,升角γ的合理范围为60°~80°,m的合理范围为1.2~1.4,L_1、L_3的合理范围为(1~1.5)d。
In order to overcome the time-consuming problems of multiple loading, multiple loading and bar machining caused by repeated repeated passes of accumulated plastic deformation under the traditional isometric angular extrusion, the ultra-fine grain structure age-hardened aluminum alloy is prepared without damage, A new method of large plastic deformation of parallel rotary isochronous extrusion is proposed. In the process, a plurality of shear deformation zones are set in one channel, and the direction and the shearing angle of the round bar are changed by setting a rotary channel between the two equal-diameter angular extrusion channels to realize the Bc processing route and improve the uniform deformation Sex. Orthogonal experiment method was used to select the internal angle Φ, external angle Ψ, angle of rise γ, ellipse factor m, and the length of the straight passage in the first passage L_1 of the second passage as the factors. Finite element simulation In the finite element extrusion simulation. The effects of equivalent strain, equivalent stress, damage amount and deformation uniformity coefficient on the extrusion process were analyzed. The simulation results show that the reasonable range of internal angle Φ is 90 ° ~ 120 °, the reasonable range of external angle ψ is 30 ° ~ 40 °, the reasonable range of lift angle γ is 60 ° ~ 80 °, and m is reasonable The range of 1.2 ~ 1.4, L_1, L_3 reasonable range of (1 ~ 1.5) d.