Effect of temperature and grain size on the dominant diffusion process for superplastic flow in an AZ61 magnesium alloy
Effect of temperature and grain size on the dominant diffusion process for superplastic flow in an AZ61 magnesium alloy
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DOI：
10.1016/s1359-6454(99)00253-0
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发表时间：
1999-10
期刊：
影响因子：
9.4
通讯作者：
H. Watanabe;T. Mukai;M. Kohzu;Shigenori Tanabe;K. Higashi
中科院分区：
文献类型：
--
作者：
H. Watanabe;T. Mukai;M. Kohzu;Shigenori Tanabe;K. Higashi
为了全面理解主要的扩散过程，研究了温度和晶粒尺寸对一种相对粗晶（~ 20 μm）Mg-Al-Zn合金超塑性流动的影响。拉伸试验表明，应变速率与晶粒尺寸的平方和应力的二次方成反比。在523-573 K范围内，激活能与晶界扩散激活能接近，在598-673 K范围内，激活能与晶格扩散激活能接近。通过对应力指数、晶粒尺寸指数和激活能的分析，认为温度和晶粒尺寸是影响扩散过程的主要因素。结果表明，有效扩散系数的概念解释了实验结果。
The effect of temperature and grain size on superplastic flow was investigated using a relatively coarse-grained (∼20 μm) Mg–Al–Zn alloy for the inclusive understanding of the dominant diffusion process. Tensile tests revealed that the strain rate was inversely proportional to the square of the grain size and to the second power of stress. The activation energy was close to that for grain boundary diffusion at 523–573 K, and was close to that for lattice diffusion at 598–673 K. From the analysis of the stress exponent, the grain size exponent and activation energy, it was suggested that the dominant diffusion process was influenced by temperature and grain size. It was demonstrated that the notion of effective diffusivity explained the experimental results.