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以 2 0 90合金和 2 0 90 +Ce合金为研究对象 ,对两合金不同时效时间的室温拉伸断口进行了半定量分析 ,探讨了拉伸性能对断裂特征的响应关系 ,并进一步分析了Ce的作用。研究表明 :2 0 90合金与 2 0 90 +Ce合金的断裂方式均以韧窝、分层开裂和沿亚晶界开裂 3种方式为主 ,随时效时间的延长 ,韧窝减少 ;分层先增加 ,后减少 ;沿亚晶界开裂比例逐渐加大。2 0 90 +Ce合金的韧窝比例较 2 0 90合金的大 ,沿亚晶界开裂比例少 ,分层开裂始终为主要断裂机制。分层开裂倾向与时效程度有密切关系。Ce通过净化合金 ,强化晶界 ,抑制共面滑移达到增塑作用。但其对抑制共面滑移有双重影响 ,使其增塑效应随时效程度不同而异。欠时效和过时效状态增塑作用较弱 ,峰值时效状态作用明显。
Taking 2090 and 2090 + Ce alloys as the research objects, the semi-quantitative analysis of the tensile fracture at room temperature for different aging time of the two alloys was carried out, and the relationship between the tensile properties and the fracture characteristics was discussed. The Ce Role. The results show that the fracture modes of 2 0 90 alloy and 2 0 90 + Ce alloy are dominated by dimples, delamination cracking and cracking along subgrain boundaries. The dimples decrease with the aging time increasing. Increase, then decrease; along the subgrain boundary cracking ratio gradually increased. The proportion of dimples in 2 0 90 + Ce alloy is larger than that in 2 0 90 alloy, with a small proportion of cracking along the subgrain boundaries, and delamination cracking is always the main fracture mechanism. Delamination cracking tendency and the degree of aging are closely related. Ce through the purification of alloys, strengthening the grain boundary, inhibition of coplanar slip to plasticize. However, it has a double impact on the inhibition of coplanar slip, which makes the plasticizing effect vary with the degree of aging. Under-aging and over-aging plasticity is weak, the effect of peak aging state is obvious.