EAGER: Hot Extrusion of High-Strength Aluminum Alloys with Rotary Porthole Dies

由于其出色的强度重量比，高强度铝合金被广泛应用于汽车、国防和航空航天工业，以及建筑和任何需要减轻重量的地方。在这些材料上使用的不同制造方法中，热挤压是生产具有恒定横截面的零件的最有效的生产工艺。然而，即使在非常高的温度下，一些有吸引力的铝合金的挤压性也很低，限制了其更广泛的应用。这个探索性研究（EAGER）项目旨在通过探索一种新的热挤压工艺的可行性来解决这个问题。如果成功，这项研究将扩大到研究更广泛的合金的性能，最终将提高高强度铝的生产率。所取得的基础科学技术进步也将适用于其他难挤压合金。由于优质铝合金可以在许多行业中使用，因此比目前可能的更大的重量减轻将成为常规。此外，由于挤压是一个接近净形状的过程，精加工操作将减少，这些航空航天合金的成本可以降低。该项目将为改进铝合金挤压提供一种新的挤压方法和科学发现，并通过金属流动控制为挤压其他难挤压合金创造一个模型。由于设想的旋转舷窗模具概念的全面探索与高风险和成本相关，在这个EAGER项目中，旋转舷窗模具的概念将通过一组固定的扭曲凹槽模具来演示。在以前的工作中，在传统的舷窗模具中观察到材料的微结构变化。这一发现表明，旋转舷窗模具可能允许控制材料流动，以传递微观结构的变化，从而提高生产。本研究将涉及一个试验台与扭转槽舷窗模具的生产，以证明这一过程。同时，将对旋转舷窗模具中的金属流动进行建模研究。了解金属流动路径及其对微观结构的影响，作为温度和变形等工艺变量的函数，将能够控制挤出产品的机械性能并提高工艺效率。目标是为这种新的制造工艺提供概念验证，从而为广泛使用难以成型的轻质合金提供途径。

Due to their outstanding strength-to-weight ratios, high-strength aluminum alloys are widely used in the automotive, defense, and aerospace industries, as well as in construction and anywhere weight savings are desired. Among the different manufacturing methods used on these materials, hot extrusion is the most efficient production process to produce parts with a constant cross-section. However, even at very high temperature, some attractive aluminum alloys have very low extrudability, limiting their wider application. This EArly-concept Grant for Exploratory Research (EAGER) project is intended to solve this problem by exploring the feasibility of a new hot extrusion process with a rotary porthole die. If successful, the research will be expanded to investigate performance of a wider range of alloys, which ultimately will increase production rate of high-strength aluminum. The fundamental scientific and technological advances made will also be applicable to other difficult-to-extrude alloys. Because superior aluminum alloys could then be used across many industries, greater weight savings than is currently possible would become routine. In addition, because extrusion is a near net-shape process, finishing operations would be reduced and the cost of these aerospace alloys could decrease.This project will deliver a new extrusion method and scientific findings for improving the extrusion of aluminum alloys, and create a model for extruding other difficult-to-extrude alloys, via metal flow control. Since the full-scale exploration of the envisioned rotary porthole die concept is associated with high risk and cost, in this EAGER project the concept a rotary porthole die will be demonstrated through a set of stationary twist-grove dies. In previous work, in-process material microstructural changes have been observed in conventional porthole dies. This finding suggests that a rotary porthole die might allow the control of the material flow to impart microstructural changes, resulting in production improvements. This research will involve the production of a testbed for with a twist-groove porthole die to demonstrate the process. At the same time, modeling will be performed to investigate metal flow in rotating porthole dies. The understanding of the metal flow path and its effects on microstructure, as a function of process variables such as temperature and deformation, will enable the control of the mechanical properties of the extruded products and increase the process efficiency. The goal is to provide a proof-of-concept of this new manufacturing process, which then provides a path for widespread use of difficult-to-form lightweight alloys.