高强度铸造铝铜合金微观组织对性能的影响

研究了微观组织对ZL205A系铸造铝铜合金热处理后强度和塑性的影响。结果表明:影响该合金强度和塑性性能的微观组织主要是晶粒尺寸、晶内、晶界沉淀相,弥散析出相和未固溶相。晶界处主要是θ相、N相、初生T相的混合组织,当呈针状或条状时恶化合金性能,当呈半连续的骨骼对合金性能影响较小。晶内细小弥散的二次T相是主要强化相,当T相聚集长大会降低强度。过剩相θ相,当呈大块分布时降低合金塑性,当呈细小均匀分布时对合金性能影响较小。

Influence of Microstructure on Mechanical Properties of High Strength Cast Aluminum-copper Alloy

The influences of microstructure on strength and ductility of high strength cast Al-Cu alloy wih heat treatment were studied.The results show that the main factors which have an influence on the strength and plasticity of Al-Cu alloy are crystalline size,precipitated phases in grain boundary,and dispersed and undissolved phases.The microstructure of the grain boundary phase is mixture structure which consists of matrix,θ(Al_2Cu),a little N,and T (Al_(12)Mn_2Cu).The mixed phases with acicular shape can depress the mechanical performance of Al-Cu alloy,while the mixed phase with incontinuous skeleton profile can improve the mechanical properties of the alloy.The fine dispersed T phase in intracrystalline is one ofthe main strengthening phases for Al-Cu alloys,but which can decrease the strength of Al-Cu alloy when T phase aggregations or grain growth happens.The ductility of the alloy reduces when the undissolved θ phase presents block shape,however,the ductility is less influenced when the undissolved θ phase is finely distributed in matrix or grain boundary.