TiAl合金過濾材料
( 中南大學 粉末冶金國家重點實驗室， 長沙 410083)
摘 要: 以Ti、 Al元素粉末為原料， 通過冷軋成形和兩階段反應合成法， 制備出孔隙度為38.3%~48.2%的Ti-46.5%Al（摩爾分數(shù)）金屬間化合物過濾材料。具有最大孔隙度為48.2%的TiAl合金過濾材料的制備工藝為： 冷軋壓力35.3×104~43.1×104 N（軋輥直徑200mm）， 燒結過程升溫速率0.33K/s， 分別在873和1473K溫度下保溫50和60min。 研究表明： 真空燒結后， TiAl合金由TiAl和Ti3Al兩相組成， Ti3Al相含量隨燒結溫度升高而增加；所制備的TiAl合金過濾材料的最可幾孔徑可達2.56μm， 對應的最大孔徑為11.8μm，透氣度為3.219×10-5 m·Pa-1·s-1； 原軋坯中的孔隙及Al元素偏擴散造孔是形成過濾材料孔隙的主要原因。
關鍵字: TiAl合金；元素粉末； 軋制； 真空燒結； 過濾材料； 偏擴散
TANG Yi-wu, HUANG Bai-yun
（ 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
