【摘要】 通过与金属型铸造对比试验,研究了挤压铸造工艺对2A70合金及热处理工艺的影响。结果表明:2A70合金在压力下凝固,增加了液相过冷度和晶体生长速度,减轻了S(Al2CuMg)相、Al9FeNi相等中间相的偏析程度,并在一定程度上细化了合金的胞晶组织,使时效相在晶内细小、弥散析出,Al9FeNi相在晶界处分布更加均匀细小。同时,消除了铸件的气孔和疏松等缺陷,提高铸件的致密度;挤压铸造铸件的组织不存在明显的方向性,力学性能达到了2A70变形铝合金的水平;挤压铸造2A70合金热处理工艺为:固溶处理加热530℃、保温3h;时效处理加热190℃、保温12h。更多还原

【Abstract】 Mechanical properties and heat treatment parameters of 2A70 alloy processed by the squeeze casting were studied through the contrast experiments of the metal mould casting process.It indicates that the degree of super-cooling in liquid phase and the rate of crystal growth are increased while the solidification of 2A70 alloy is carried under the pressure,the segregation degree of the interphases,such as S(Al2CuMg),Al9FeN,is alleviated.To a certain extent,the grain refining of the cellular crystal was observed and the aging phase is thinly and dispersively separated out.Al9FeNi is more thinly and uniformly distributed in the grain boundary.Simultaneously,the defects such as air hole,porosity are erased.The density is increased.The microstructure in squeeze casting alloy is non-orientedly.It has the same mechanical property as the wrought aluminum alloy 2A70 has.The heat treatment process of the squeeze casting 2A70 alloy is : solution treatment in 530 ℃/3 h,aging treatment in 190 ℃/12 h.更多还原