Process Simulation of Friction Extrusion of Aluminum alloys

The friction extrusion process (FEP) is a solid-state material processing technique in which a translating extrusion die is pressed against a billet/feedstock material in a rotating extrusion container to produce an extruded rod or wire. A key aspect of FEP is the non-equilibrium thermo-mechanical condition created at the contact region between the die and billet, leading to a possibly improved microstructure. Numerical simulations of FEP are highly complex due to contact between the tool and the workpiece, and interplay between thermo-mechanical conditions and the present severe plastic deformation. In the present work, a three-dimensional finite element model is developed to study the material flow behavior for different extrusion ratios for a 60° die angle during friction extrusion. The developed model is numerically validated against experimental data. The spatial temperature, strain and velocity distributions illustrate the effect of extrusion ratio on the deformation characteristics of the extruded aluminum alloys, thereby assisting in experimental microstructure interpretation.摩擦挤压工艺（Friction Extrusion Process, FEP）是一种固态材料加工技术，具体工艺为将移动挤压模具压靠于旋转挤压筒内的坯料/进料材料之上，以此制备挤压棒材或线材。该工艺的核心特征在于，模具与坯料的接触区域会形成非平衡热机械状态，有望改善材料的微观组织。由于刀具与工件间存在接触，且热机械状态与当前剧烈塑性变形之间存在相互耦合作用，摩擦挤压工艺的数值模拟极具复杂性。本研究针对模具角度为60°的摩擦挤压工艺，开发了三维有限元模型，以探究不同挤压比下的材料流动行为。所开发的模型通过与实验数据对比完成了数值验证。空间温度、应变与速度分布阐明了挤压比对挤压铝合金变形特性的影响，从而可为实验微观组织的解析提供辅助。