摘要
采用拉伸试验、TEM、SEM等测试手段,研究了不同多级时效热处理下汽车轻量化用Al-Mg-Zn-Cu-Sn铝合金的力学和组织性能。研究结果表明:合金基体中存在白色的粗大第二相组织,主要存在AlZnMgCu相与Al7Cu2Fe杂质相。二级时效处理后在晶粒中形成了许多细小析出相,合金晶界析出η相。对合金进行时效处理时生成强化相沉淀的顺序是先转变为α过饱和固溶体,再进入GP区,之后形成η’相,最终转变为η相。对合金进行二级时效处理后,产生众多GP区与η’相,起到明显的强化效果。采用二级时效方法进行处理后,合金拉伸强度与屈服强度达到641. 05 MPa与596. 42 MPa,伸长率12. 16%。在合金的断口区域形成了沿晶断裂与穿晶韧窝断裂,经过二级时效处理后形成许多韧窝状的穿晶断口;经过三级时效处理后有些韧窝深度与外径都较大。
Mechanical and microstructure properties of Al-Mg-Zn-Cu-Sn aluminum alloy for automotive lightweight were studied by means of mechanical tensile testing,TEM,SEM and other test methods.The results show that there are white coarse secondary phases in the alloy matrix,mainly Al Zn MgCu phase and Al7Cu2Fe impurity phase.After secondary aging treatment,many fine precipitate phases are formed in the grains,ηphase at the grain boundary of the alloy.In the aging process of the alloy after obtainingαsupersaturation solid solution,the order of enhanced phase precipitate formation is GP zone,thenη’phase,finallyηphase.After secondary aging treatment of the alloy,many GP zones andη’phases are produced,which has obvious strengthening effect.The tensile strength and yield strength of the alloy reach 641.05 MPa and 596.42 MPa,respectively,and the elongation is 12.16%.Intergranular fracture and transgranular dimple fracture are formed in the fracture region of the alloy,and many dimple-like transgranular fractures are formed after secondary aging treatment.The depth and diameter of some dimples are larger after three-step aging.
作者
董晨
汤玲娜
傅康
Dong Chen;Tang Lingna;Fu Kang(Department of Mechanical Engineering,Shangrao Institute of Vocational Technology,Shangrao Jiangxi 334109,China;Department of Electronic Engineering,Shangrao Institute of Vocational Technology,Shangrao Jiangxi 334109,China)
出处
《金属热处理》
CAS
CSCD
北大核心
2019年第9期200-203,共4页
Heat Treatment of Metals
