热障涂层平头压痕蠕变研究

研究典型热障涂层(thermal barrier coating，TBC)系统在圆柱形平头压痕下的蠕变响应。考虑刚性压头、弹性压头和弹性磨损压头作用下，压头压痕深度随时间的变化规律和压头前方的Mises应力分布，分析压头尺寸和外载荷变化对压痕深度和Mises应力分布的影响．可以得出结论，平头压痕下TBC系统的蠕变在较短时间内即达到稳态，压痕深度随外载荷和压头半径的增大而增大；在相同载荷和压头半径下，压痕深度的影响表现为弹性磨损心头大于弹性压头，弹性压头大于刚性压头；对于弹性磨损压头，在相同载荷和压头半径下，压痕深度随磨损圆角半径的增大而增大。

STUDY OF INDENTATION CREEP OF THERMAL BARRIER COATING SYSTEMS USING CYLINDRICAL INDENTERS

Finite element method was used to investigate the creep behavior when cylindrical indenters impressed into thermal barrier coating(TBC) systems. Emphasis was placed on the effects of indenter shape, indenter sizes and applied loads. Three different kinds of indenters were used. They were rigid indenters, elastic indenters and elastic worn indenters. FEM results gave curves of indentation creep depth d as a function of creep time t and Mises stress ahead of the indenters. Some conclusions have been drawn. First, with cylindrical indenters the creep of TBC systems can reach steady state in a short time. Second, the impression depths increase with the increase of indenter sizes and applied stresses. Third, at the same indenter size and stress the impression depth of the worn elastic indenter is deeper than that of the elastic indenter and the rigid indenter. Four, for worn elastic indenters, at the same indenter size and stress the impression depths increase with the increase of the worn rim radius. The study of the indention creep responses of TBC systems with cylindrical indenters gives better understanding of creep performances of TBC systems and it is a basis to determine creep parameters of each layer of TBC systems.