加载速率对Al膜纳米压入蠕变性能的影响

EFFECT OF LOADING RATE ON NANOINDENTATION CREEP PROPERTIES OF Al FILMS

纳米压入仪对Si片上晶Al膜进行的压入蠕变实验表明,加载方式对Al膜的蠕变性能有明显影响.随加载速率和载荷的增大, Al膜的总蠕变量和应力指数均有较大升高 且蠕变初期可能存在异常高蠕变率.分析认为这与是加载过程中未及发生的塑性变形的持续释放有关.对于确定的薄膜材荆及组织结构,加载过程中积攒的塑性变形量及其释放速率将影响不同加载条件下的总蠕变量和应力指数.

Constant loading rate/load creep experiments were conducted on polycrystalline Al thin films using nanoindentation instrument. The results indicated that the loading mode has an obvious effect on the creep properties. With increasing loading rate/load, total creep and stress exponent of the film were increased. The high creep rate in an initial loading stage was considered the result of the release of plastic deformation, which should have taken place in the loading of previous segment. It follows that the change of total creep and stress exponent of tested films depends sometimes on the amount of plastic deformation under different loading conditions.