Ti-B20钛合金的时效特征

Aging characteristics of Ti-B20 alloy

研究了Ti-B20合金(以'临界钼当量条件下的多元强化'为原则设计的一种新型的高强度亚稳β钛合金)在不同热处理条件下的时效组织和拉伸性能.结果表明:同常见的亚稳β钛合金相比,Ti-B20合金具有更快的时效响应及更高的时效强化效应,其析出相更加细小均匀;合金在α-β区固溶后在500～600℃时效时可以获得优良的强度和塑性匹配(抗拉强度:1 200～1 500MPa;延伸率:8%～18%),高温时效时没有发现无析出区;合金在β区固溶后的时效强度要大大高于α-β区固溶后的时效强度,但却会导致拉伸塑性的急剧降低.所有的这些时效特征都来源于合金成分的独特性.

The aging microstructures and properties of Ti-B20 alloy, a new high strength metastable beta titanium alloy which was designed according to the principle of ‘critical molybdenum equivalence and multi-components strengthening’, were investigated under different heat treatment conditions. The results show that compared to traditional metastable β titanium alloys, Ti-B20 alloy has more rapid aging response, much higher aging strengthening effect and much finer but homogeneous depositions. After α-β solution and 500600℃ aging treatment, excellent strength and plasticity properties can be achieved(ultimate tensile strength: 12001500MPa; elongation: 8%18%) and no precipitate-free regions have been found during high temperature aging treatment. Beside, the aging strength of alloy after solution treatment in β region is considerably higher than that in α-β region. But β solution and aging treatment will lead to remarkable decrease of tensile ductility. All these aging characteristics of Ti-B20 alloy are responsible for its specific components.