TiAl合金过滤材料
( 中南大学 粉末冶金国家重点实验室， 长沙 410083)
摘 要: 以Ti、 Al元素粉末为原料， 通过冷轧成形和两阶段反应合成法， 制备出孔隙度为38.3%~48.2%的Ti-46.5%Al（摩尔分数）金属间化合物过滤材料。具有最大孔隙度为48.2%的TiAl合金过滤材料的制备工艺为： 冷轧压力35.3×104~43.1×104 N（轧辊直径200mm）， 烧结过程升温速率0.33K/s， 分别在873和1473K温度下保温50和60min。 研究表明： 真空烧结后， TiAl合金由TiAl和Ti3Al两相组成， Ti3Al相含量随烧结温度升高而增加；所制备的TiAl合金过滤材料的最可几孔径可达2.56μm， 对应的最大孔径为11.8μm，透气度为3.219×10-5 m·Pa-1·s-1； 原轧坯中的孔隙及Al元素偏扩散造孔是形成过滤材料孔隙的主要原因。
关键字: TiAl合金；元素粉末； 轧制； 真空烧结； 过滤材料； 偏扩散
（ State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: Ti-46.5%Al(mole fraction) intermetallic compound filter materials with overall porosity of 38.3%-48.2% were fabricated through elemental powder cold roll forming and reactive synthesis. The TiAl alloy filter material with maximum porosity was fabricated under cold pressure of 35.3×104-43.1×104 N(with the roller diameter of 200mm), heating rate of 0.33K/s, and thermal retardation time of 50 and 60min at 873 and 1473K, respectively. The results show that the microstructure of TiAl filter material consists of TiAl and Ti3Al phases, and that the content of Ti3Al phase increases with the sintering temperature. The most probable aperture of the TiAl alloy filter material is 2.56μm, and its maximum aperture and air permeability are 11.8μm and 3.219×10-5 m·Pa-1·s-1, respectively. The prime reasons are considered to be the existence of the porosity in sheet bars and Al self-diffusion in the process of reactive synthesis.
Key words: TiAl alloy; elemental powder; rolling; vacuum sintering; filter material; partial diffusion
