| 引用本文: | 曹富荣,崔建忠,丁桦,侯红亮,李志强.不同初始组织材料超塑性m值模型与验证[J].哈尔滨工业大学学报,2015,47(10):50.DOI:10.11918/j.issn.0367-6234.2015.10.011 |
| CAO Furong,CUI Jianzhong,DING Hua,HOU Hongliang,LI Zhiqiang.Modeling the mvalue and its experimental verification during superplasticity of materials with different initial microstructures[J].Journal of Harbin Institute of Technology,2015,47(10):50.DOI:10.11918/j.issn.0367-6234.2015.10.011 |
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| 摘要: |
| 为确定超塑性机理和本构方程,需要计算m值.采用铸造、轧制和退火方法获得细晶AA7075铝合金板材,采用高温拉伸机和图像分析仪研究了合金m值的变化,针对等轴晶粒和带状晶粒的材料超塑性变形,建立了m值与应变关系模型.模型证明等轴晶粒组织恒速度超塑性变形m值随应变增加而减小和带状晶粒组织超塑性变形m值随应变增加而增大. 理论预测得到等轴细晶AA7075铝合金和AA7475+0.7Zr 铝合金和带状晶粒的Mg-8.5%Li 合金和包含小角度晶界的AA7475铝合金超塑性实验结果的支持.模型预测与实验结果吻合,内在组织变化是m值变化的根本原因. |
| 关键词: 超塑性 应变速率敏感性 应变 空洞 动态再结晶 |
| DOI：10.11918/j.issn.0367-6234.2015.10.011 |
| 分类号:TG136 |
| 基金项目:国家自然科学基金(51334006). |
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| Modeling the mvalue and its experimental verification during superplasticity of materials with different initial microstructures |
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CAO Furong1, CUI Jianzhong2,DING Hua1, HOU Hongliang3, LI Zhiqiang3
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（1.School of Materials and Metallurgy, Northeastern University，110819 Shenyang, China;2.Key Laboratory of Electromagnetic Processing of Materials, Ministry of Education（Northeastern University），110819 Shenyang, China;3.Professor of AVIC Beijing Aeronautical Manufacturing Technology Research Institute, 100024 Beijing, China）
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| Abstract: |
| In order to ascertain superplastic mechanism and establish constitutive equation, strain rate sensitivity exponent (mvalue) is required to be calculated. Fine-grained AA7075 aluminum alloy sheets were fabricated by casting, rolling and annealing, and variation in the mvalues were investigated by high temperature tensile machine and image analyzer. Aiming at the superplastic deformation of materials with the equiaxed grain and the elongated grain microstructures, the relations between the mvalue and the strain were modeled. It is noted that the mvalue for the equiaxed grain microstructure decreases with increasing the strain during constant velocity tension, and the mvalue for the elongated grain microstructure increases with increasing the strain during superplasticity. Theoretical predictions were verified by the superplastic experimental evidence in AA7075 alloy and AA7475+0.7Zr alloy with fine equiaxed grains and in Mg-8.5%Li alloys with the elongated grains and AA7475 alloy with low angle grain boundaries. The calculated results agree well with the experimental ones, and it is shown that variation in microstructure leads to the variation in the mvalue. |
| Key words: superplasticity strain rate sensitivity exponent strain cavitation dynamic recrystallization |
