Effect of Heating Rate on Superplasticity Properties and The Superplastic Cavitation of AA 5083 Al-Mg-Mn Alloy

• Main Authors: Tang, 林裕棠
• Other Authors: Jun-Yen Uan
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/00293984298816874707

碩士 === 國立中興大學 === 材料工程學研究所 === 93 === Abstract Different heating rate of heat treatment brings about a corresponding change in the degree of pre-existing cavities healing after a large deformation process with AA5083 Al-Mg-Mn alloy. The initial defects produced by rolling process at the particle–matrix interface that cause continuous nucleation of cavities are important for the superplasticity of Al-Mg alloy in a general superplastic forming. The configuration of small cavities ( less than 0.5 μm) were detected by scanning electron microscopy and the volume fraction of cavities was measured by precise density measurement equipment. With subsequently tensile experiment in high temperature, the elongation of specimens in rapid heating rate was better than specimens which in slow heating rate. Phenomenally, cavitation often precedes failure and excessive cavitation may impose significant limitations on the industrial use of superplastic forming. The cavitation of deformed specimens were detected in different elongation without failed and rapid heating process before loading significantly decreases the cavitation rate during subsequent superplastic forming.