【摘要】 以2090+Ce合金为研究对象,测试不同时效温度、时间的断裂韧性,并对试样断口进行半定量分析,探讨时效工艺、断裂韧性及断裂机制之间的响应关系。研究表明,2090+Ce合金的断裂韧性试样以分层开裂为主要断裂方式。分层开裂与时效温度有密切关系,随时效温度升高,分层比例增大,厚度变薄。分层开裂亦与应力状态、晶界强度有密切关系,分层裂纹最先在三向应力的作用下于试样中心的晶界处形成,平行承载的薄板处于平面应力状态,裂尖前方塑性区扩大,消耗较多塑性变形功,从而达到增塑作用。时效温度和时间对断裂韧性临界裂纹尺寸影响很小。更多还原

【Abstract】 The fracture toughness of 2090+Ce aluminum-lithium alloys aged for different temperature and time is determined, and the fracture is analyzed by means of semi-quantity method. The relationship among the process parameter, fracture toughness and fracture mechanisms is discussed. The results show that the main fracture features are delamination. There is a close relationship between the aging temperature and the delamination. At higher temperature, the delamination percentage increases and the thickness decreases. The delaminationcan be significantly influenced by the stress state either. The first delamination crack occurs at the center grain boundary of specimen as a result of the three dimension tension stress. The parallel thicker segment is in plane-stress condition, the enlarged plastic area in front of the crack absorb more plastic energy, which improve the fracture toughness properties. There is little effect of temperature on the critical crack.更多还原