AZ91D鎂合金經應變導引熔漿活化法（SIMA）之顯微結構研究

Abstract

在半固態成形的過程中，製程條件的控制與材料的流變性質是影響產品品質的重要關鍵。材料的流變性質，主要是受材料於半固態黏漿狀態下的顯微結構所影響，如晶粒的型態愈接近等軸狀，則流動性愈佳，而晶粒的尺寸愈小，則產品的機械性質愈好。本研究以AZ91D鎂合金為材料，採用K. P. Young所提出的應變導引熔漿活化法（Strain Induced Melt Activated，SIMA）為半固態黏漿的製造方法，藉由控制施於材料的壓縮應變量、半固態溫度與持溫時間等三個參數，並利用田口式參數設計規劃實驗，探討材料於不同的參數組合下的顯微結構變化，嘗試找出具有最佳流動性的材料顯微組織之形成條件。

During semi-solid forming process, the process parameter combination and the rheological behavior of the material are key factors affecting the quality of product. The rheological behavior is mainly affected by the microstructure of material in semi-solid state. For example, the more spherical the grain shape, the better the flow-ability; the smaller the grain size, the better the mechanical properties of the product. This study prepared the semi-solid slurry of AZ91D alloy with the Strain Induced Melt Activated (SIMA) process proposed by K. P. Young , applied compression on the work piece, adjusted temperature of material and holding time in semi-solid state, and explored the microstructure under different parameter combinations. The experiment plan was constructed by Taguchi method.