等温锻造对Ti-17粉末合金显微组织的影响

Effect of Isothermal Forging on Microstructure of Ti-17 Powder Alloy

采用烧结+等温锻造的方法制备Ti-17粉末合金,对粉末合金制备过程中各工序的密度、显微组织变化规律等进行了试验研究。试验结果表明:经相同条件烧结后,-140目粉末烧结棒材和-80/+140目粉末烧结棒材分别达到理论密度的98.06%和93.55%,在-80/+140目粉末烧结棒材显微组织中观察到有大量的残留空隙存在。采用高低温等温锻造工艺能够有效去除粉末合金烧结后残留的空隙,提高合金的密度,使合金的显微组织得到显著细化和均匀化。烧结+等温锻造是制备优质粉末钛合金的有效方法。

Ti-17 powder alloy was prepared by the method of sintering ＋ isothermal forging, and the densities and transformation of mierostructure in the process of preparing powder alloy were investigated. The results indieate that the relative densities of - 140 mesh sintering bar and -80/＋ 140 mesh sintering bar are 98.06% and 93.55% respectively at the same conditions of sintering, and a number of voids remained in the microstrueture of - 80/＋ 140 mesh powder sintering bar. The high and low isothermal forging can remove the remaining void effectively after powder alloy sintering, consequently increase the density and get refined and uniform microstructure. Thus the ssintering ＋ isothermal forging is an effective way of preparing high quality powder titanium alloys.