摘要
对7075铝合金进行深冷-时效复合处理(DCT-T6),使用TEM、SEM和拉伸测试等手段对其表征,研究了深冷-时效复合处理对其显微组织和力学性能的影响。结果表明,与T6处理相比,DCT-T6处理可提高晶内析出相密度、减小析出相的尺寸、提高位错密度和生成亚晶。在深冷时间为3~6 h时,随着深冷时间的延长η’相的密度先提高后降低,晶界析出相(GBP)的尺寸、两相间距、线缺陷数量、η相密度、位错密度以及亚晶数量增大,合金的伸长率降低,抗拉强度先提高后降低。深冷4 h为拐点。深冷时间为4 h时合金的抗拉强度达到最大值645 MPa,比T6样品提高13.1%;深冷时间为3 h时合金的伸长率达到最大值13%,比T6样品提高了44.4%。
The 7075 Al-alloy was subjected to T6 aging treatment at deep cryogenic temperature(DCT-T6) via soaking in liquified nitrogen, and its precipitation phase, dislocation density and tensile properties were assessed by means of TEM, SEM and tensile testing techniques. The results show that the DCT-T6 could increase the density of intra-grain precipitated phases, reduce the size of precipitated phase, increase the dislocation density and the formation of sub-grain, in comparison with the conventional T6 treatment. In the range of 3~6 h, with the increase of soaking time, the η’ phase density increases and then decreases, and the inflection point is 4 h;the size of grain boundary precipitated phase(GBP)and the phase spacing, the number of linear defects, η phase density, dislocation density and the number of sub-grains all increase constantly;the tensile strength of the alloy increases and then decreases, and the elongation constantly decrease. When the soaking time was 4 h, the tensile strength of the alloy reached a maximum value of 645 MPa, which was 13.1% higher than that of the T6 alloy;when the soaking time was 3 h, the elongation of the alloy reached a maximum value of 13%, which was 44.4% higher than that of the T6 alloy.
作者
余聪
陈乐平
江鸿翔
周全
杨成刚
YU Cong;CHEN Leping;JIANG Hongxiang;ZHOU Quan;YANG Chenggang(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China;Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China)
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2023年第2期120-128,共9页
Chinese Journal of Materials Research
基金
国家自然科学基金(51765046)
江西省研究生创新专项基金(YC2021-S670)。
