等通道转角挤压对耐热镁合金AZ61-4Si组织及性能的影响

Effect of Equal Channel Angular Pressing on Microstructure and Properties of AZ61-4Si Heat-Resistant Magnesium Alloy

摘要:

研究了镁合金AZ61-4Si等通道转角挤压前后的微观组织与力学性能。结果表明：经4道次挤压后汉字状Mg2Si相细化为细小颗粒状，基体α-Mg与离异共晶相β-Mg17Al12也得到细化；合金的屈服强度提高128%，伸长率提高340%，抗拉强度提高89%，高温蠕变断裂寿命提高8倍，蠕变速率为0.058%/h。与4道次相比，经8道次挤压后微观组织没有明显变化；屈服强度有所提高，抗拉强度和延伸率有所降低，高温蠕变断裂寿命有所下降，蠕变速率有所提高。对等通道转角挤压改善实验合金微观组织及力学性能机理进行了分析

Abstract:

The microstructure and mechanical properties of AZ61-4Si magnesium alloy before and after equal channel angular processing (ECAP) were studied. The results show that Chinese script type Mg2Si phase changes into fine granules after 4-pass ECAP. The matrix α-Mg and divorced eutectic β-Mg17Al12 are also refined. The yield strength, elongation and tensile strength are increased by 128%, 340% and 89%, respectively. The high temperature creep fracture life increases by 8 times and the creep rate is 0.058%/h. Compared with the 4-pass ECAP, the microstructure shows little change after 8-pass ECAP. The yield strength and creep rate of the 8-pass ECAPed alloy are improved while the yield strength, elongation and high temperature creep fracture life are reduced. The modification mechanism for microstructure and mechanical properties of the experimental alloy by ECAP was analyzed