Sesearch on the mechanism of debonding process on the matrix-reinforcement interface of metai-matrix composites and the development of the method of analysis

本项目所取得的成果总结如下：1。采用单元胞模型对sic晶须增强铝合金的蠕变损伤进行了数值模拟。蠕变损伤始于晶须边缘，随后发生脱粘。建立了MMC淬火过程的有限元程序。孔洞的形成和由孔洞引起的损伤沿界面进行。颗粒分散MMC：采用离心铸造法制备了分散在SiC颗粒中的铝。通过实验阐明了铸造条件对颗粒径向分布的影响。建立了考虑颗粒运动的基于熔融基体凝固的弹粘塑性应力分析有限元程序。实验结果证实了该程序的有效性。表面改性MMC：通过模拟陶瓷在金属表面的爆轰包覆过程，提出了一种有限元程序。发现涂层中存在较大的拉应力。在双轴载荷作用下，米塞斯型等效应力可以控制包铝不锈钢爆轰层的破坏。利用分子动力学方法对溅射过程进行结构分析表明，锚点效应是界面键合的主要机制。

Results obtained in the present project are summarized as follows ;1.Fiber-reinforced MMC : Creep damage in an SiC-whisker reinforced Al allpy was numerically simulated by using a unit cell model. The creep damage was revealed to initiate at the edge of whisker, from which a subsequent debonding developed. An FEM code was established for quenching process of MMC.The formation of voids and progress of damage initiated from voids were found to occur along the inteface.2.Particle-dispersed MMC : Alminum dispersed with SiC particles was processed by a centrifugal casting method. The effect of casting condition on the radial distribution of particles was clarified experimentally. A FEM code for elastic-viscoplastic strees analysis was constructed based on the solidification of molten matrix considering the particle motion. The validity of the code was confirmed by experimental results.3.Surface-modified MMC : A FEM code was proposed by modeling the detonation-coating process of ceramics on a metal surface. A large tensile stress was found to occur in coated layr. The equivalent stress of Mises type may control the failure of detonation-coated layr in an alumina-coated stainless steel under biaxial loading. Structural analysis using a molecular dynamics procedure developed for sputtering process suggested that an anchor effect was the main mechanism of interface bonding.