脉冲电流处理对7075铝合金显微组织及力学性能的影响  

Effect of electron pulse treatment on microstructure and mechanical properties of 7075 aluminum alloy

作　　者：余聪 陈乐平[1] 周全[1] 袁源平 YU Cong;CHEN Le-ping;ZHOU Quan;YUAN Yuan-ping(School of Aeronautical Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学航空制造工程学院,江西南昌330063

出　　处：《材料热处理学报》2023年第9期51-60,共10页Transactions of Materials and Heat Treatment

基　　金：江西省科技重点研发计划项目(20212BBE53018)。

摘　　要：对7075铝合金进行T6时效处理和不同电流密度(50~125 A/mm^(2))、不同通电时间(480~600 ms)的脉冲电流处理(EPT),采用扫描电镜、透射电镜及万能试验机等研究了合金经不同工艺处理后的显微组织和力学性能。结果表明:与传统的T6时效处理相比,采用合适的电流密度和通电时间的脉冲电流处理,合金的析出相数量、尺寸减小,但能提高位错密度和亚晶数量;且随电流密度和通电时间的增加,第二相回溶数量和亚晶数量不断增加,但位错密度随着电流密度的增加先增大后减小,随着通电时间的增加而不断减小。合金的抗拉强度和伸长率随电流密度和通电时间的增加均为先升高后降低,经固溶+EPT(470℃×3 h+100 A/mm^(2)×560 ms)后合金的抗拉强度和伸长率达到最高,分别为555 MPa和18%,与T6时效处理相比,抗拉强度下降了2.6%,但伸长率提高了100%。脉冲电流处理的合金的强化机制是固溶强化、位错强化和细晶强化的复合强化机制。7075 aluminum alloy was subjected to T6 aging treatment and electron pulse treatment(EPT)with different current densities(50-125 A/mm^(2))and different electrification time(480-600 ms).Microstructure and mechanical properties of the alloy after different process treatments were studied by means of scanning electron microscopy,transmission electron microscopy and universal testing machine.The results show that compared to traditional T6 aging treatment,electron pulse treatment with appropriate current density and electrification time can reduce the number and size of precipitates in the alloy,but can increase dislocation density and subgrain quantity.And with the increase of current density and electrification time,the number of second phase resolution and subgrains continuously increases,but the dislocation density first increases and then decreases with the increase of current density,and continuously decreases with the increase of electrification time.The tensile strength and elongation of the alloy first increase and then decrease with the increase of current density and electrification time,and after solution treatment+EPT(470℃×3 h+100 A/mm^(2)×560 ms),the tensile strength and elongation of the alloy reach the highest,which are 555 MPa and 18%,respectively.Compared with T6 aging treatment,the tensile strength decreases by 2.6%,but the elongation increases by 100%.The strengthening mechanism of the alloy after electron pulse treatment is a composite strengthening mechanism of solution strengthening,dislocation strengthening and fine grain strengthening.

关 键 词：7075铝合金 脉冲电流处理 显微组织 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程]