(哈爾濱工業(yè)大學 材料科學與工程學院，哈爾濱 150001)
摘 要: 在應變速率為0.005~1 s−1、溫度250~350 ℃條件下，采用Instron-5500熱模擬機對AZ91D鎂合金的高溫壓縮特性進行研究，得到其真實應力—應變曲線。分析擠壓溫度和應變速率等對曲線的影響，得出本構(gòu)方程的一系列常數(shù)，建立AZ91D鎂合金在高溫壓縮中的本構(gòu)方程關(guān)系式。結(jié)果表明：變形過程中AZ91D鎂合金的流動應力隨溫度的升高而降低，隨應變速率的升高而升高；該流動應力可以用雙曲正弦函數(shù)來描述，其雙曲正弦值隨Zener-Hollomon參數(shù)自然對數(shù)的升高呈線性增大；AZ91D鎂合金是正應變速率敏感材料，其應變速率敏感指數(shù)m=0.14。
關(guān)鍵字: AZ91D鎂合金；高溫壓縮；流變應力；Zener-Hollomon參數(shù)
（School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:The compression tests of AZ91D magnesium alloy at elevated temperature were carried out on Instron-5500 at strain rates ranging from 0.005 to 1 s−1 and deformation temperate between 250 and 350 ℃. The true stress—strain curves were obtained and the influences of deformation temperature and strain rate on the curves were analyzed. The constitutive equation and some constants of AZ91D magnesium alloy during compression deformation were gained. The results show that during the compression, the flow stress of AZ91D magnesium alloy decreases with increasing deformation temperature whereas it increase with increasing strain rates. The flow stress of AZ91D magnesium alloy at elevated temperature can be described with the hyperbolic sine function, and the hyperbolic sine value of flow stress will increase linely with increasing natural logarithm of Zener-Hollomon parameter. The strain rate sensitivity index (m) of AZ91D magnesium alloy is equal to 0.14.
Key words: AZ91D magnesium alloy; elevated temperature compression; flow stress; Zener-Hollomon parameter
