(华中科技大学 材料科学与工程学院 材料成形与模具技术国家重点实验室，武汉 430074)
摘 要: 采用透射电子显微镜、单向拉伸力学性能测试和扫描电子显微镜等方法研究了2195铝锂合金在不同形变热处理下时效析出行为，并阐明了析出相强化机理。结果表明：不同形变热处理下2195铝锂合金中主要强化相均为T1相，但是其尺寸、分布、数量密度和晶界形貌有差异。预应变可显著提高T1相的形核率并加速其长大过程。时效温度越高，T1相的形核率越低，但长大速度越快。形变热处理后的微观组织可显著提高2195铝锂合金的力学性能，T871态(固溶处理+7%预应变+(120 ℃、4 h)+(160 ℃、24 h))的屈服强度为(541±10) MPa，抗拉强度为(606±9) MPa，伸长率为(11±1)%。位错在T1相多处沿着垂直于直径方向剪切，有效阻止了微观尺度上的塑性局部化。
关键字: 2195铝锂合金；微观组织；形变热处理；力学性能
（State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:In this paper, the microstructure and mechanical properties of 2195 Al-Li alloy under different thermo-mechanical processing(TMP) were studied by transmission electron microscope, uniaxial tensile mechanical property test and scanning electron microscope. The aging precipitation behavior was analyzed and the strengthening mechanism of precipitates was clarified. The results show that the main strengthening phase under different TMP is T1 phase, but its size, distribution, quantity density and grain boundary morphology are different. Pre-strain can significantly increase the nucleation rate of T1 phase and accelerate its growth process. The higher the aging temperature, the lower the nucleation rate of T1 phase, but the faster the growth rate. Microstructures formed by TMP can significantly improve the mechanical properties of 2195 Al-Li alloy. The yield strength, tensile strength and elongation of T871 state (solution treatment+7% pre-strain+(120 ℃, 4 h)+(160 ℃, 24 h)) are (541±10) MPa, (606±9) MPa and (11±1)%, respectively. The dislocation shears along the direction perpendicular to the diameter of T1 phase at multiple locations, which effectively prevents plastic localization on the micro-scale.
Key words: 2195 Al-Li alloy; microstructure; thermo-mechanical processing; mechanical property
