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Microscopic analysis of deformation and fracture of metal matrix composites

金属基复合材料变形与断裂的微观分析

基本信息

批准号：
09650749
负责人：
SASAKI Gen
金额：
$ 2.3万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

The metal matrix composites were fabricated by the squeeze casting, semi-solid casting, stirring casting and the hot pressing. Reinforcements used in this study are mainly SiC, AlィイD218ィエD2BィイD24ィエD2OィイD233ィエD2, TiOィイD22ィエD2 particles/whisker/fiber and matrices are aluminum, magnesium and titanium alloys. Furthermore, Niobium/MoSiィイD22ィエD2 lamellar composites were fabricated by hot pressing. At first, the relationship between the fabrication condition and the mechanical properties were investigated. Then, in order to investigate the control factor of the mechanical properties, the microstructure, the deformation and the fracture structure were observed in atomic scale by the scanning and transmission electron microscopy. The main control factors are the deterioration of the reinforcement, the structure changes of the ceramics/matrix interface and the change of the matrix microstructure (or character). We focused the investigation of the effect of interface structure and reaction on the deformation and fracture. By considering the control method of the interface structure, we presented the design principle of the composite fabrication.Following is the topics in this study. Interface reaction temperature of TiOィイD22ィエD2/Al composite decreased by the doping the third element for the surface of the TiOィイD22ィエD2 particles. Heat stability of the AlィイD218ィエD2BィイD24ィエD2OィイD233ィエD2 whisker / Al, Mg alloy matrix composites increased by the formation of the thin and homogeneous MgAlィイD22ィエD2OィイD24ィエD2 layer on the whisker. Nb/MoSiィイD22ィエD2 lamellar composites having high fracture toughness was fabricated by the addition of the third elements to MoSiィイD22ィエD2 sheet. In fiber-reinforced composites, it is found that the creep rupture lifetime was predicted by the probability model considering the time dependence of the load resistance of the fiber.

采用挤压铸造、半固态铸造、搅拌铸造和热压等工艺制备了金属基复合材料。本研究所用的增强体主要为碳化硅、AlィイD218ィエD2BィイD24ィエD2OィイD233ィエD2、TiOTiOD22ィイD2颗粒/晶须/纤维，基体为铝、镁和钛合金。在此基础上，采用热压法制备了Nb/MoSiィイD22ィエD2层状复合材料。首先，研究了制备条件与力学性能之间的关系。在此基础上，利用扫描和透射电子显微镜对材料的微观组织、形变和断口组织进行了原子尺度的观察，以探讨其力学性能的控制因素。主要控制因素是增强体的劣化、陶瓷/母材界面的结构变化和母体组织(或性质)的变化。重点研究了界面结构和界面反应对变形和断裂的影响。通过考虑界面结构的控制方法，给出了复合材料制备的设计原则。在ィイD22ィエD2颗粒表面掺杂第三种元素，降低了复合材料的界面反应温度。AlィイD218ィエD2BィイD24ィエD2OィイD233ィエD2晶须在晶须上形成了较薄且均匀的ィイD22ィエD2OィイD24ィエD2层，从而提高了复合材料的热稳定性。通过在MoSiィイD22ィエD2板材中添加第三种元素，制备了具有高断裂韧性的Nb/MoSiィイD22ィエD2层状复合材料。在纤维增强复合材料中，考虑纤维载荷阻力随时间变化的概率模型可以预测材料的蠕变断裂寿命。