Effect of precipitation on internal friction of AZ91 magnesium alloy

• Published in: Transactions of Nonferrous Metals Society of China 2010-07, Vol.20 (B07), p.453-457
• Main Author: 刘树伟 姜海昌 李秀艳 戎利建
• Format: Article
• Language: English
• Subjects: aging; AZ91镁合金; Dynamic tests; Grain boundaries; Internal friction; isothermal treatment; Magnesium base alloys; Precipitation; Scanning electron microscopy; Solid solutions; solutionization; Thermal relaxation; X射线衍射分析; 不连续析出; 不连续沉淀; 动态力学分析; 弛豫内耗峰; 扫描电子显微镜
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(10)60517-1

The effect of precipitation on the internal friction（IF）of AZ91 magnesium alloy was investigated by using X-ray diffraction（XRD）analysis,scanning electron microscope（SEM）observation,and dynamic mechanical analysis（DMA）.Six different states of alloy were prepared by applying different heat treatment processes：as-cast,in-complete solid solution,complete solid solution,micro-precipitation,continuous precipitation and continuous-discontinuous precipitation.It was found that the internal friction of in-completely solid-solutionized,completely solid-solutionized and micro-precipitated specimens showed a similar characteristic,and the grain boundary relaxation is completed depressed due to the Al atoms supersaturated in theα-Mg solution.However,a thermal relaxation internal friction peak was observed for continuously precipitated and continuously-discontinuously precipitated specimens at around 438 K and frequency of about 1 Hz,which was attributed to the grain boundaries relaxation.Furthermore,it was found that the relaxation of theβ-Mg17Al12/α-Mg phase interfaces should give its contribution to the background internal friction in the as-cast,continuously precipitated and continuously-discontinuously precipitated specimens.