热加工对冷喷涂铝合金块材性能的影响

Effect of hot working on properties of cold sprayed aluminum alloy bulk

为了提高冷喷涂增材制造铝基块材性能,对低压冷喷涂法沉积的7075铝合金块材进行了后续退火和热轧加工。采用光学显微镜和扫描电镜观察试样的组织结构特征,并通过拉伸试验和电化学测试表征了块材的应力-应变曲线和耐蚀性。结果表明,低压冷喷涂法沉积的铝合金块材结构上存在大量的颗粒界面和少量微孔等缺陷,拉伸时发生脆性断裂,塑性很差,耐点蚀性能差;经过400℃退火4 h后,结构缺陷显著减少;再经过30%压下量的热轧加工后,结构更加致密,强度和韧性均提高,耐蚀性也随着结构缺陷的减少而提高。

In order to improve properties,7075 aluminum alloy bulks prepared by low-pressure cold spraying were further processed by annealing and hot rolling.The microstructure characteristics of the bulks were observed by means of metallographic microscope and scanning electron microscope,and the stress-strain curves and corrosion resistance were characterized by tensile test and electrochemical test.The results show that a large number of particle interfaces and a small number of micro-holes exist in the structure of cold sprayed aluminum alloy bulks,which leads to brittle fracture,poor plasticity and poor pitting corrosion resistance.After annealing at 400℃for 4 h,the structural defects of the spraying deposited bulks are significantly reduced.After hot rolling with 30%reduction,the structure of the spraying deposited bulks is more compact and the strength and toughness are improved,and the corrosion resistance increases due to the reduction of structural defects.