摘要
分别用3种不同粒度的氮气雾化2A12铝合金粉末为原料,采用热等静压法制备2A12铝合金,研究粉末粒度对合金组织与力学性能的影响。结果表明:热等静压可实现2A12铝合金粉末的近全致密化,粉末粒径越小,粒径分布范围越广,则致密化程度越高,同时几何尺寸收缩较大,压坯的相对密度最高达到97.6%;粒度较大的粉末经过热等静压后,颗粒边界趋于平直,边界与边界的夹角趋于均匀的120°,而粒度较小的粉末原始边界严重变形,部分小颗粒甚至融合在一起;随粉末粒度减小及粒径分布范围增大,Al和Cu等合金元素的析出相由点状连续分布变为集中分布在粉末颗粒的三向交叉处,微观组织更致密均匀,颗粒边界细小,颗粒之间的扩散连接加强。粒度最小的2A12铝合金粉末经热等静压后,析出的合金元素第二相对合金有强化作用,抗拉强度和伸长率都提高,分别达到306 MPa和10.5%。
By using 2A12 aluminium alloy powders with three kinds of particle size（The average particle size is 195.81, 123.58 and 34.9 μm respectively） as raw material, 2A12 aluminium alloy was prepared in a way of hot isostatic pressing（HIP）. The effect of particle size on mechanical property, micro morphology, microstructure evolution and element migration of P/M aluminium alloys was analyzed. The result shows that hot isostatic pressing（HIP） can achieve densification for 2A12 aluminium alloy powders. The smaller the particle size and the greater the powder distribution range are, the higher the degree of densification is. The relative density of pressed compacts reaches 97.6%. In the meantime, the high relative density leads to the great shrinkage of specimen size. The boundary among particles become flat and the boundaries＇ angle tends to 120° for big particles after HIP. However, the boundary among small particles is seriously deformed and some of small particles even fuse together after HIP. The distribution of precipitated phase which is rich in Cu/Al transforms from continuously stellate distribution to concentrated distribution in three-way junction among particles with the decrease of powder size and the increase of size-distributed region, which increases diffusion bonding strength, makes inner organization and boundary between the particles fine. For the smallest size of the 2A12 aluminium alloy powders, tensile strength and elongation of P/M aluminium alloy are improved after HIP, because of strengthening effect of precipitates during the process of HIP. The tensile strength and elongation of specimen reach 306 MPa and 10.5%.
出处
《粉末冶金材料科学与工程》
EI
北大核心
2016年第1期85-94,共10页
Materials Science and Engineering of Powder Metallurgy
关键词
2A12铝合金粉末
热等静压
粉末粒径
微观组织
力学性能
2A12 aluminum alloy powder
hot isostatic pressing
powder size
microstructure
mechanical property
