时效温度对Ti-29Nb-13Ta-4.6Zr合金组织及摩擦磨损性能的影响

利用真空熔炼制备了Ti-29Nb-13Ta-4.6Zr合金铸锭,对合金在800 ℃固溶处2 h后在300~500 ℃下进行等时时效,研究时效温度对合金的组织结构和摩擦磨损性能的影响。结果表明:800 ℃固溶2 h后水冷的合金是单一过冷亚稳近β组织,低温时效后,样品中出现了弥散的α相,而当时效温度超过450 ℃以上时α相不再呈弥散分布,而是在晶界处富集。随着时效温度的升高,合金的硬度逐渐增高,到500 ℃时达到最高253 HV0.3,然后快速降低;摩擦因数同样随着时效温度的增高呈现先升高后降低的规律。450 ℃时效的样品的综合性能最好,摩擦因数较小,且磨损试样出现了粘着磨损的特征。

Effect of aging temperature on microstructure and friction properties of Ti-29Nb-13Ta-4.6Zr alloy

Ti-29Nb-13Ta-4.6Zr alloy ingot was prepared by vacuum melting. After solid solution treatment at 800 ℃ for 2 h, isothermal aging was carried out at 300-500 ℃ to study the microstructures and wear resistance of the alloy via aging hardening. The results show that, the alloy has a metastable undercooling near-β single-phase microstructure after solid solution treatment. After low temperature aging, the dispersed α phase appears inside the grains, however, at the temperature above 450 ℃ the α phase is no longer dispersively distributed but enriched at the grain boundaries. With the increase of aging temperature, the hardness of the alloy increases gradually and reaches the maximum of 253 HV0.3 at 500 ℃, and then decreases rapidly, while the friction coefficient also increases first then decreases with the increase of aging temperature. The comprehensive properties of the samples aged at 450 ℃ is the best, which has smaller friction coefficient and exhibits adhesive wear characteristics.