摘要
采用分级淬火法测定了7085铝合金的TTT和TTP曲线,并结合透射电镜对其淬火敏感性进行了研究。结果表明,在等温保温过程中7085铝合金淬火态电导率升高,时效态硬度下降,在中间温度段电导率及硬度变化较快;TTT和TTP曲线的鼻尖温度约为320℃,淬火敏感区间为250~370℃;等温保温过程中,过饱和固溶体分解析出平衡相η,在320℃附近析出速率达到最大,随着等温保温时间的延长,η相聚集并长大,时效后出现大量无沉淀析出区域,导致性能显著下降;在淬火敏感区间,较高的相变驱动力和较大的扩散速率是η相快速析出长大的主要原因。
The time-temperature-transformation（TTT）curve and time-temperature-property（TTP）curve of 7085 aluminum alloy were determined by an interrupted quench technique.The microstructure transformation during isothermal treatment was studied by the transmission electron microscopy（TEM）.Our experiment confirmed an electro-conductivity increasing trend and a hardness decreasing trend of the 7085 alloy during isothermal treatment,both of which change faster in the moderate temperature range.The nose temperatures of the TTT and TTP curves are about 320 ℃ and the high quench sensitive temperature ranges from 250 ℃to 370 ℃.Microstructure observation indicated that the supersaturated solid solution decomposes and equilibriumηprecipitates,and the precipitation rate reaches the highest value at about 320℃.ηparticles precipitate,agglomerate and grow as the isothermal treatment processes,which results in loss of solutes and decrease of the property.In the quench sensitive range,ηparticles＇ rapid precipitation and growth can be attributed to high diffusion rate of solute atoms and large driving force of phase transformation.
作者
肖靖
易幼平
崔金栋
黄始全
XIAO Jing;YI Youping;CUI Jindong;HUANG Shiquan(State Key Laboratory of High Performance Complex Manufacturing,Central South University,Changsha 410083;School of Mechanical and Electrical Engineering,Central South University,Changsha 410083)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2018年第12期1998-2002,共5页
Materials Reports
基金
江苏省科技计划(BA2015075)
国家国际科技合作专项(2014DFA51250)
