LY12合金率相关变形的微观机制分析  

Micro-Mechanisms of Rate Dependent Tensile Deformation for LY12 Aluminium Alloy

作　　者：吴艳青[1] 

机构地区：[1]北京理工大学爆炸科学与技术国家重点实验室,北京100081

出　　处：《稀有金属材料与工程》2007年第12期2109-2113,共5页Rare Metal Materials and Engineering

摘　　要：LY12合金经历高温低应变速率拉伸延伸率达到17%时,将其冷却至室温,在室温下拉伸,性质会发生很大变化:流变应力只有普通室温屈服应力的1/10左右;延伸率增加1倍左右。该现象与高温拉伸速率、温度、冷却方式密切相关。而经历高温高应变速率拉伸达到17%的延伸率,再在室温下拉伸的试样,则呈现出类似脆性的变形行为。利用透射电镜分析,从析出相和亚结构角度探讨了对应于不同宏观行为的微结构变化特征,并结合SEM断口分析,揭示了相应的断裂模式和断裂机制。The great change of LY 12 alloy property took place after the alloy underwent high temperature and low strain rates （elongation up to 17%） followed by room-temperature tension. It was found that the flow stress of LY 12 aluminum alloy reduced to only ten percent of the yield point after undergoing high-temperature deformation at low strain rate （10^-4 s^-1）, and the elongation to fracture increased by one time. This abnormal room-temperature property strongly depends on the tensile strain rates and temperature and the cooling rate. By comparison, the sample subjected to high-temperature deformation at higher strain rate （10^-1 s^-1） showed brittle-like behavior after cooled up to room temperature, i.e. a sudden increase in flow stress and rupture quickly. From the point view of precipitate and substructures, the characteristics of microstructure are described by TEM analyses. Combined with SEM fracture surface analysis, the corresponding fracture mode and mechanisms are expatiated.

关 键 词：LY12铝合金 率相关变形:析出相:亚结构 

分 类 号：TG111.5[金属学及工艺—物理冶金]