变形参数对AZ31B镁合金直齿圆柱齿轮热锻过程中变形和显微组织演变的影响（英文）

Effects of forging parameters on uniformity in deformation and microstructure of AZ31B straight spur gear

应用有限元模拟和统计分析方法研究变形参数对直齿圆柱齿轮成形过程中变形和显微组织演变的影响。将有限元方法与显微组织演化模型相集成建立了基于浮动凹模设计的齿轮成形有限元模型。采用Gleeble热力模拟实验和定量金相分析技术获得镁合金高温流动应力曲线和动态再结晶模型。数值模拟和实验检验表明,由于齿轮形状复杂,且坯料与模具间存在接触摩擦,齿轮各部位变形和显微组织存在不均匀现象。变形温度降低或者变形速率增加,有利于获得平均晶粒尺寸细小的组织,但是变形和显微组织不均匀性增大,其原因和流动应力曲线特征有关。

The effects of forging parameters on the deformation and microstructure distributions of as-forged straight spur gears wereinvestigated by finite element(FE)simulation and statistical analysis method.Spur gear forging using the movable cavity die designwas investigated by integrating the FE method with the microstructure evolution models for AZ31B magnesium alloys.The requiredinputs such as flow stress curves and microstructure evolution models,were obtained through the Gleeble thermal mechanical testingand quantitative metallography analysis method.Numerical simulation and experimental examination confirm that both thedeformation and microstructure are non-uniformly distributed in the as-forged gears.Decreasing deformation temperature orincreasing strain rate is beneficial to obtaining fine-grained microstructure but is harmful to the uniformity in deformation ormicrostructure.The level of the non-uniformity results from the complex shape of gear and the friction between the billet and dies,which is closely associated with the characteristics of flow stress curve.