Ti-Al合金板材
( 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， 在粉末軋機上無包套冷軋成尺寸為500 mm×230 mm×1.5 mm的板坯， 其相對密度達85.9%。 研究了不同工藝參數(shù)對Ti、 Al元素粉末軋制板材的影響。 取小樣在不同溫度下進行真空無壓燒結(jié)， 研究了板坯的真空燒結(jié)行為。 結(jié)果表明： Ti、 Al元素粉末冷軋過程要求適中的粉末流動性、 低的軋制速度以及一定大小且較穩(wěn)定的軋制壓力。 真空燒結(jié)后， Ti-Al合金由Ti-Al和Ti3Al兩相組成， Ti3Al相含量隨燒結(jié)溫度升高而增加。 燒結(jié)坯孔隙度大幅度增加， 增加量為21%~32%。 原板坯中的孔隙及偏擴散是造成燒結(jié)坯孔隙的主要原因。 低壓（<10 kPa）真空燒結(jié)過程中， 外壓僅有效作用于短暫的液相階段， 粉末粒度越粗， 燒結(jié)溫度越高， 燒結(jié)坯孔隙度受這種低壓強的影響程度越大。
關(guān)鍵字: Ti-Al合金；元素粉末； 軋制； 真空燒結(jié)； 板材
LI Zhi, HUANG Bai-yun
（ State Key Laboratory of Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract: Ti-Al alloy sheets were fabricated successfully by element powder cold roll forming and reactive synthesis. The size and relative density of sheet bars were 500 mm×230 mm×1.5 mm, 85.9% respectively. The effects of process parameters on the fabrication of sheet bars and the vacuum sintering behavior of sheets at different temperatures were investigated. The results show that the moderate flowability of element powders, low rolling velocity and stable rolling pressure are needed for the process of Ti, Al element powder cold rolling. After the sintering, microstructure of Ti-Al alloy sheet consists of Ti-Al and Ti3Al phases, and the content of Ti3Al phase increases with the sintering temperature. The increment of Ti-Al sheets porosity is 21%-32%, and 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. During the low pressure(＜10 kPa) vacuum sintering process, the external pressure works effectively in the transient liquid phase stage. The effect of the low external pressure on porosity of sintered sheets increases with the increment of the size of the element powder particles and the sintering temperature.
Key words: Ti-Al alloy; element powder; cold roll; vacuum sinter; sheet
