小能量多冲法对物理气相沉积膜层机械性能的评价

利用自行研制的小能量多冲试验装置,对物理气相沉积(PVD)方法制备的CrMo合金膜和TiA lN陶瓷膜的结合强度、韧性、内聚强度等机械性能进行综合评价;探讨了膜层性质、冲头几何形状、基材硬度等因素对PVD膜层在小能量多冲条件下失效行为的影响规律;比较了膜层在承受动态多冲与静态压入载荷条件下失效行为的异同;分析了膜层在小能量多冲条件下的失效机制。结果表明:小能量多冲法能够很好地模拟膜层承受动态冲击载荷的服役工况。该方法既可以用于评价硬质陶瓷膜层的机械性能,也可用于合金膜层的力学性能表征;冲击力比冲击周次对膜层多冲失效行为的影响更为显著;四棱锥冲头较球型冲头更易于造成膜层的剥落失效,因而更有利于评价膜层的结合强度;承载能力高的基材有利于提高膜层的多冲抗力;膜层在四棱锥冲头多冲条件下主要发生膜基结合型破坏,而在静载压入条件下的失效则以开裂为主,反映了膜层的韧性及内聚强度。

Evaluation of Mechanical Properties of Physical Vapour Deposited Coatings Using Impact Test with Low Energy

A self-made impact tester with low energy was used to evaluate the adhesion,cohesion and toughness etc of physical vapor deposited(PVD) CrMo and TiAlN coatings.The influence of coating characteristic,impact body geometry and substrate hardness on the failure behaviors of the PVD coatings under low impact load was explored.The similarities and differences between the coating failure modes under impact and static press load were investigated,and the failure mechanisms of the coatings bearing impact load were discussed.The results show that the impact test can better simulate the work conditions of the coatings enduring dynamic impact load.The impact tester can be used to evaluate the mechanical properties of both hard ceramic coatings and alloy coatings.The impact force has more remarkable influence on the coating failure than impact cycles.The rectangular pyramid impact body is more suitable for evaluating the coating adhesion than the tungsten carbide ball because the rectangular body easily induces coating delamination.The impact resistance of the coatings can be increased by the substrate with high load bearing capacity.Adhesive failure mainly occurs on the coatings when the rectangular pyramid body is used,while the coatings predominantly fail in cracking mode under static press load which reflects the cohesion and toughness of the coatings.