2198铝锂合金对时效温度敏感性及其析出行为

Sensitivity of 2198 Al-Li Alloy to Aging Temperature and Its Precipitation Behavior

摘要:

通过拉伸测试和透射电镜分析，研究了不同时效温度下2198铝锂合金组织和性能的变化。结果发现：在峰时效之前的小温度区间内，2198铝锂合金对时效温度非常敏感，经淬火变形后在150～170 ℃下时效14 h，随温度的升高，强化效果显著增加，延伸率降低；观察到的2198合金的析出相相主要是δ′、θ′、β′/δ′、T-1、σ相。不同时效温度下得到的析出相的种类和形貌不同，160 ℃以下时效，析出相以δ′、θ′、β′/δ′为主，160 ℃以上，以T-1、σ相的为主，多种相复合强化。时效过程中析出相的种类和含量的变化是该合金力学性能对时效温度敏感的本质原因

Abstract:

The effect of aging temperature on the microstructure and tensile properties of 2198 Al-Li alloy were investigated by tensile test and TEM. The results show a great dependence of tensile properties on aging temperature in a narrow temperature region before peak aging. When the temperature (150 °C~170 °C /14 h) increases, the tensile strength rises dramatically; meanwhile the tensile elongation decreases. The main precipitates detected in 2198 alloy are δ′, θ′, β′/δ′, T-1 and σ phase. The combination and morphology of precipitates vary with different aging temperatures; the main precipitates are δ′, θ′, β′/δ′ when aging below 160 °C, while above 160 °C, T-1 and σ phases come out in large numbers, and become the dominating strengthening phases gradually. It is concluded that the sensitivity of 2198 Al-Li alloy to aging temperature is essentially attributed to the variety and amount of precipitates