摘要
采用旋转永磁体搅拌工艺制备半固态A356铝合金浆料并进行流变压铸,研究热处理工艺对流变压铸样件本体力学性能的影响,并采用扫描电镜(SEM)和能谱分析仪(EDS)进行显微组织分析。结果表明:采用T51热处理时,当人工时效时间为3h时,σ_b=290 MPa、δ=8.5%,此时δ达到最大值;延长人工时效时间,σ_b缓慢提高,但是δ下降;采用T6热处理时,当人工时效时间为1h,σ_b=310 MPa、δ=16.5%;当人工时效时间4.5h时,σ_b=335MPa、δ=10.5%,此时σ_b达到最大值,δ达到最小值。T6热处理后,当人工时效时间为1h,试样断口具有大量的撕裂棱和韧窝,在晶界处产生大量富Si的鹅卵石形状的强化相,当量直径小于4μm。同时,在α(Al)基体内形成大量富Si和富Mg的GP区和亚稳相,还产生大量直径小于1μm的Al、Si和Mg的氧化物,并钉扎在α(Al)基体内,与GP区和亚稳相共同对α(Al)基体起强化作用。
Semisolid A356 aluminum alloy slurry was prepared and rheo-diecasted by rotating permanent magnet stirring process. The effect of heat treatment process on the mechanical properties of rheo-diecasting samples was studied, and microstructure of the samples was analyzed by scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDS）. The results show that when T5_1 heat treatment is used, after being artificially aged for 3 h, σ_b is 290MPa, δ is 8.5%, at this time, δ value reaches the maximum. When artificial aging time is prolonged, σ_b value increases slowly, whereas δ value decreases. When T6 heat treatment is used, after being artificially aged for 1h, σ_b=310MPa, δ=16.5%. After being artificial aged for 4.5h, σ_b=335MPa, δ=10.5%, at this time, σ_b value reaches the maximum, whereas δ value reaches the minimum. After T6 heat treatment, and being artificially aged for 1h, a large number of torn edges and dimples are produced on the sample fracture surface, and a large number of pebble-shape strengthening phases with rich Si are produced at the grain boundaries, whose equivalent diameter is within 4μm. At the same time, substantial GP zones with rich Si and rich Mg and metastable phases form in α（Al） matrix, and a large number of Al, Si and Mg oxides with diameter less than 1μm are produced and pinned in α（Al） matrix. These oxides play an important role in strengthening the α（Al） matrix with the GP zones and metastable phases.
作者
陈正周
宋朝辉
罗文博
CHEN Zheng-zhou;SONG Chao-hui;LUO Wen-bo(Cixi Huili Machinery and Electric Co., Ltd., Cixi 315333, China;Cixi ALT advanced material Co., Ltd., Cixi 315301, China;School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2018年第3期518-527,共10页
The Chinese Journal of Nonferrous Metals
关键词
A356铝合金
力学性能
显微组织
热处理
流变压铸
A356 aluminum alloy
mechanical property
microstructure
heat treatment
rheo-diecasting
