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本文介绍了快速凝固Al4Li1.5CuMg0.2Zr合金的粉末制造、除气、热挤压及热处理工艺过程。并对材料的拉伸性能,低循环疲劳性能及微观机制做了较为详细的研究。采用快速凝固方法制成Al4Li1.5CuMg0.2Zr合金,温度在500℃固溶处理1h,时效8h后抗拉强度达到620MPa以上,延伸率稳定在4%以上。密度小于2.41,比强度达到25.25,优于传统的Al-Li合金。经过电镜分析证明合金的延伸率不能显著提高的主要原因是δ′相与S′相不能很好地匹配,且有T2粗大相的析出。利用德国的Schenck疲劳式样机对该合金进行了低周疲劳试验,得到了εNf和σε曲线以及材料的疲劳性能参量,并发现了合金的裂纹萌生的主要原因是试样内部存在着冶金缺陷。通过本试验的研究将为快速凝固AlLi合金的进一步研制打下良好基础。
This article describes the powder solidification Al4Li1.5CuMg0.2Zr alloy, degassing, hot extrusion and heat treatment process. And the tensile properties of materials, low cycle fatigue properties and micro-mechanisms made a more detailed study. Al4Li1.5CuMg0.2Zr alloy was prepared by rapid solidification method. The solution was treated at 500 ℃ for 1h. The tensile strength reached 620MPa after 8h aging, and the elongation was more than 4%. The density is less than 2.41 and the specific strength is 25.25, which is better than the traditional Al-Li alloy. After the electron microscopy analysis shows that the elongation of the alloy can not significantly increase the main reason is the δ ’phase and the S’ phase does not fit well, and T2 coarse facies precipitation. The low cycle fatigue test was carried out on this alloy by the German Schenck fatigue prototype. The εNf and σε curves and the fatigue performance parameters of the alloy were obtained. The main reason for the crack initiation was found to be metallurgical defects in the sample. Through the study of this experiment will lay a good foundation for the further development of rapidly solidified AlLi alloy.