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Al Li合金的工艺塑性较低 ,存在高温沿晶脆性断裂现象 ,其断裂机制至今国内外都未进行系统的研究。采用Gleeble 150 0热模拟试验机 ,对铸态 142 0Al Li合金在变形温度t为 350～ 4 50℃、应变速率 ε为 0 .0 1～ 10s- 1的条件下 ,进行了高温拉伸热模拟实验研究。在实验基础上 ,研究了 142 0Al Li合金的高温拉伸断裂行为。结果表明 ,随着变形温度和应变速率的提高 ,142 0Al Li合金高温拉伸断裂模式由典型的穿晶韧性断裂转变为沿晶脆性断裂。研究说明 ,氢是引起 142 0Al Li合金高温沿晶脆性断裂的根本原因 ,并对 142 0Al Li合金高温氢致断裂的机理进行了探讨 ,提出了“高温氢脆是由于动力和静力二者综合作用的结果”的观点 ,丰富和发展了氢脆理论。
Al Li alloy has low plasticity and brittle fracture at high temperature. The fracture mechanism of Al Li alloy has not been systematically studied at home and abroad. The hot deformation simulation of hot-cast 142 0Al Li alloy was carried out at a temperature of 350-450 ℃ and a strain rate ε of 0.01-10s-1 using a Gleeble 150 0 thermal simulator. Experimental Study. Based on the experiment, the tensile fracture behavior of 142 0Al Li alloy at high temperature was studied. The results show that the high temperature tensile fracture mode of 142 0Al Li alloy transforms from typical transgranular ductile fracture to intergranular brittle fracture with the increase of deformation temperature and strain rate. The results show that hydrogen is the fundamental cause of high temperature brittle fracture of 142 0Al Li alloy and the mechanism of hydrogen induced fracture at high temperature of 142 0Al Li alloy is discussed. The “high temperature hydrogen embrittlement is due to the combination of dynamic and static Role of the results of ”point of view, enriched and developed hydrogen embrittlement theory.