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| 2A97 铝锂合金超塑变形规律及其本构方程 |
| Superplastic Deformation Law and Constitutive Equation of 2A97 Al-Li Alloy |
| Received:January 11, 2015 Revised:March 10, 2015 |
| DOI：10.3969/j.issn.1674-6457.2015.02.007 |
| 中文关键词: 2A97 铝锂合金 超塑性 本构方程 |
| 英文关键词: 2A97 Al- Li alloy superplasticity constitutive equation |
| 基金项目:国家重点基础研究发展计划(国家973 计划)(2011CB012803);国家自然科学基金(51405457) |
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| 中文摘要: |
| 目的 研究2A97 铝锂合金在390 ~470 ℃温度范围和3×10-4 ~3×10-2 s-1 应变速率范围内的超塑变形行为,揭示温度和应变速率对延伸率和峰值应力的影响规律,并建立超塑拉伸变形本构方程。方法 采用单轴超塑拉伸试验方法进行研究。结果 当变形应变速率低于3×10-3 s-1时,2A97 铝锂合金真应力-真应变曲线呈现稳态流变特征;当应变速率高于3×10-3 s-1 时,则呈现软化特征。在450 ℃,应变速率为1×10-3 s-1条件下,达到最大延伸率600%。结论 2A97 铝锂合金具有良好的超塑变形性能,其应变速率敏感性指数m 平均值为0. 35,超塑变性激活能Q 值为145. 87kJ/ mol,远高于纯铝自扩散激活能65. 6 kJ/ mol,表明此时铝锂合金变形机制仍以晶内滑℃为主。 |
| 英文摘要: |
| The aims of this study were to investigate the superplastic behavior of 2A97 Al-Li alloy with the deformation temperatures ranging from 390 ℃to 470 ℃and initial strain rate between 3×10-4 s-1 ~ 3×10-2 s-1 , reveal the influence law of temperature and strain rate on elongation and m value, and establish the superplastic tensile deformation constitutive equation. The research was carried out by uniaxial superplastic tensile test. When the deformation of initial strain rate was lower than 3×10-3 s-1 , the 2A97 Al-Li alloy true stress-strain curve had steady rheological characteristics; when the initial strain rate was higher than 3×10-3 s-1 , the curve had softening characteristics. And in 450 ℃/1×10-3 s-1 condition, the maximum extension rate was 600%. 2A97 Al-Li alloy had good performance of superplastic deformation, the strain rate sensitivity index m average was 0. 35, and the superplastic degeneration activation energy Q value was 145. 87 kJ/ mol, far higher than the diffusion activation energy of pure aluminum (65. 6 kJ/ mol). The result showed that the aluminum lithium alloy deformation mechanism was dominated by intracrystalline slip. |
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