热处理对A380铝合金组织性能的影响

Effects of Heat Treatment on Microstructure and Properties of A380 Aluminum Alloy

利用微量元素Sr对A380铝合金进行变质处理,并对变质后的合金进行热处理,研究Sr变质和热处理对铝合金组织性能的影响。结果表明:Sr元素能改善A380铝合金的延展性能,0.04%Sr变质可将粗大的片状共晶硅转变为细小纤维化状态。对变质后的铝合金进行490℃/15 min固溶处理、水淬+175℃/8 h的热处理后,纤维状共晶硅发生球化现象,组织结构致密化,力学性能提高,抗拉强度由铸造状态的179 MPa提升至258 MPa,伸长率由原来的3.3%提升至4.2%。断裂面为韧脆混合断裂机制,且变质热处理后,合金的摩擦系数减小。

A380 aluminum alloy was modified by Sr, and then was treated by heat treatment, and the effects of Sr modification and heat treatment on the microstructure and properties of aluminum alloy were studied. Results show that the Sr element can improve the ductility of A380 aluminum alloy, and the 0.04% Sr can be used to transform the coarse lamellar eutectic silicon into the small fibrotic state. After the treatment of 490 ℃/15 min solution and water quenching＋175 ℃/8 h, the eutectic silicon in fibrotic state is spheroidied and the microstructure of the alloy is more compact, which improves the mechanical properties, and the tensile strength increases from 179 MPa to 258 MPa, the elongation increases from 3.3% to4.2%. The fracture surface is ductile brittle fracture mechanism and the friction coefficient of the alloy decreases.