摘要
α＋βtitanium alloy with a composition of Ti-6.55Al-3.41Mo-1.77Zr （mass fraction,%） was cast into bars in a graphite mould using vacuum induction skull melting furnace （ISM）. The cast bars were hot swaged at 700 °C and then heat treated by two different regimes which resulted in fine and coarse lamella structures, respectively. The grain size of the as-cast structure was estimated to be 660 μm and the swaged samples obtained a very fine grain size in the range of 50 μm. The overall best combination of hardness, tensile properties, and wear resistance of theα＋βtitanium alloy was achieved by heat treating the samples at 1050 °C for getting fine lamellar structure. The maximum compression strength was reported for the heat treated samples at 800 °C with coarse lamella structure. The minimum wear rate was reported for the heat treated samples with fine lamellar structure and the maximum wear rate was obtained for as-cast samples due to its coarse and heterogeneity microstructure.
采用真空感应熔炼炉将成分为Ti-6.55Al-3.41Mo-1.77Zr(质量分数)的α+β钛合金在石墨模具中浇铸成棒材。铸态棒材在700°C下热锻后,通过两种不同的热处理后,分别得到细小和粗大的层片状结构。结果表明:铸态组织的晶粒尺寸约为660μm,而锻造后样品具有细小的晶粒尺寸,约为50μm。在1050°C热处理后的α+β钛合金具有细小的层片状结构,得到最佳的硬度、拉伸性能和耐磨性。在800°C热处理后的α+β钛合金具有粗大的层片状结构,具有最大的抗压强度。具有细小层片状结构的热处理态α+β钛合金的磨损率较小,而铸态α+β钛合金由于具有粗大和不均匀的微观组织,因此磨损率较大。
