半固态扩展挤压A2017合金过程中金属流动的有限元分析

Finite element modelling analysis of metal flowing during process of extending extruding semisolid A2017 alloy

应用有限元方法分析了半固态扩展挤压A2017合金过程中金属的流动规律。分析表明:从中心区域向两边侧壁,合金速度逐渐减少,有时在从中心向两边侧壁的中间区域出现涡流过渡区;不存在台阶θ时,涡流区θ较小;倾角越大,涡流区域越小,且死区较小;定径带出口越宽,出口流速越小,涡流区越小,死区也越小。设计无台阶且较小的倾角的扩展挤压模较为合理,在定径带断面的长向与宽向上,尺寸应尽量相等。

Finite element modelling method was adopted to analysis rule of metal flowing during the process of semisolid extending extrusion A2107 alloy. The results show that alloy velocity decreases gradually from the center to sides of mould wall. In the middle of the way from the center to the side of the mould, sometime, there is a transitional turbulence zone. Without step α, turbulence zone is smaller. When θ is larger, both the turbulence zone and die zone are smaller. When the exit is wide, the velocity, the turbulence zone and the die zone are smaller. Designing a mould with smaller θ and without step α is desirable. Two sides of forming zone of negative mould should be equal as possible.