【摘要】 冷喷涂技术作为一种固相增材制造技术，在制备和修复航空航天用高强铝合金部件时可有效避免材料因熔化而产生的热裂等致命缺陷，实现高性能高强铝合金的高效打印。采用Al₂O₃颗粒原位夯实的强化工艺，使用低成本的空气代替氦气成功实现致密的7075Al/Al₂O₃复合沉积层的制备，并探究了Al₂O₃颗粒含量对7075Al/Al₂O₃复合沉积层微观组织和力学性能的影响。结果表明，随着Al₂O₃颗粒含量的提高，冷喷涂7075Al颗粒的塑性变形程度增大，颗粒间的结合效果改善，孔隙等缺陷的数量减少。沉积层中的晶粒随之细化，并发生塑性变形诱导再结晶。纳米压痕结果显示，沉积层的弹性模量和硬度先升高后降低，且数值受局部应变的明显影响。沉积层的结合强度和抗拉强度均持续升高，在D-80沉积层中最大，相比D-20沉积层提高约1倍。沉积层的耐磨损性能获得明显改善，磨损形式以粘着磨损为主，磨损率显著下降。更多还原

【Abstract】 Cold spray, a solid-state additive manufacturing technology, can effectively avoid fatal defects resulted from materials melting, such as hot cracking, when preparing and repairing high-strength aluminum alloy components.Furthermore, it can print high-strength aluminum alloys with shorter production cycle.The strengthening process of in-situ hammering with Al₂O₃ particles was adopted, and low-cost air was used instead of helium to successfully prepare a dense 7075Al/Al₂O₃ composite deposit.The effect of Al₂O₃ particle content on the microstructure and mechanical properties of the 7075Al/Al₂O₃ composite deposit was explored as well.The results indicate that as the content of Al₂O₃ particles increases, the extent of plastic deformation of the cold-sprayed 7075Al particles rises, the interparticle adhesion strengthens, and the number of defects, such as pores, declines.The grains in the deposit are subsequently refined and underwent severe plastic deformation-induced recrystallization.The nanoindentation results demonstrate that the elasticity modulus and hardness of the deposit exhibit an initial increase, followed by a subsequent decrease.Notably, these values are significantly influenced by the local strain.The bond strength and the tensile strength of the deposits exhibited a consistent enhancement, with the maximum observed in the D-80 deposit and an increase of approximately one fold compared to the D-20 deposit.Furthermore, a notable improvement is discerned in the deposit′ wear resistance.Additionally, the wear form is predominantly adhesive wear, accompanied by a considerable reduction in the wear rate.更多还原