新型Al-Mg-Sc-Zr合金显微组织和性能研究  

Properties and Microstructure of Novel Al-Mg-Sc-Zr Alloy

作　　者：郭琦 徐国富[1,2] 黄继武[1,2] 尹志民[1] 邓英[1,2] Guo Qi;Xu Guofu;Huang Jiwu;Yin Zhimin;Deng Ying(College of Material Science and Engineering,Central South University,Changsha 410083,China;Key La-boratory of Nonferrous Materials Science and Engineering of Ministry of Education,Central South University,Chang-sha 410083,China)

机构地区：[1]中南大学材料科学与工程学院,湖南长沙410083 [2]中南大学有色金属材料科学与工程教育部重点实验室,湖南长沙410083

出　　处：《稀有金属》2019年第3期255-264,共10页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51601229);湖南省自然科学基金项目(2016JJ3151);青年人才托举工程项目(2015RS4001);广东省省级科技计划项目(2016B090931004)资助

摘　　要：采用半连续铸造方法制备了一种新型的Al-5.5Mg-0.078Sc-0.15Zr (%,质量分数)合金铸锭,通过性能测试和电子显微分析技术研究了该合金板材制备过程中的组织性能演变规律。结果表明:铸态合金主要由富含(Fe, Mn)杂质相和Mg_2Al_3相构成。均匀化处理过程中,可溶性金属间化合物Mg_2Al_3先析出,后逐步溶入基体中,优化的均匀化工艺为350℃×10 h+440℃×6 h。随稳定化退火温度的升高,合金的强度降低,延伸率升高,剥落腐蚀敏感性降低,腐蚀电流密度降低。Al-Mg-Sc-Zr合金板材经过330℃退火1 h后可获得最优综合性能,其中σ_b,σ_(0.2)与δ分别为424, 348 MPa和13.1%,剥落腐蚀等级为PA。研究合金具有高合金强度主要源于Al_3(Sc,Zr)粒子产生的奥罗万强化和亚结构强化作用;随稳定化温度的升高,合金内的Mg_2Al_3相在高温稳定化退火中发生了一定回溶,因此剥落腐蚀抗力提高。A new type of Al-5.5Mg-0.078Sc-0.15Zr(%,mass fraction)alloy ingot was designed by semi-continuous casting method.The microstructure and properties of the alloy sheet were studied by means of properties test and electron microscopic analysis technology.The results showed that the as-cast alloy was mainly composed of(Fe,Mn)impurity phase and Mg2Al3 phase.In the homogenization process,the soluble metallic compound Mg2Al3 precipitated first,then gradually dissolved into the matrix,and the optimized homogenization process was 350℃×10 h+440℃×6 h.With the stabilizing annealing temperature increasing,the strength of the alloy decreased,the elongation increased,the susceptibility to exfoliation corrosion decreased,and the corrosion current density decreased.The optimized comprehensive properties of Al-Mg-Sc-Zr alloy sheet after annealing at 330℃ for 1 h were obtained,in which theσb,σ0.2 andδwere 424,348 MPa and 13.1%,respectively,and the exfoliation corrosion grade was PA.The studied alloy with high alloy strength was mainly caused by Orowan strengthening and substructure strengthening effect of Al3(Sc,Zr)particles.With the increase of the stabilizing temperature,the Mg2Al3 phase in the alloy came back tomatrix during the high temperature stabilizing annealing,so the resistance to exfoliation corrosion increased.

关 键 词：AL-MG-SC-ZR合金 均匀化退火 稳定化退火 再结晶 显微组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]