(1. 中南工業(yè)大學粉末冶金國家重點實驗室，長沙 410083;
2. 哈爾濱工業(yè)大學材料科學與工程學院，哈爾濱 150001)
摘 要: 研究了粉末冶金TiAl基合金柴油機排氣閥的近型成形技術(shù)，其要點為：采用元素粉末冶金方法，以元素Ti，Al粉末為主要原料，首先在剛模中冷壓成排氣閥菌部；然后在真空熱壓爐中，通過準等靜壓工藝，同時實現(xiàn)TiAl 基合金的反應(yīng)合成與近型成形；最后通過真空擴散聯(lián)接工藝，使粉末冶金TiAl基合金菌部與鑄態(tài)TiAl基合金桿部聯(lián)接成完整的排氣閥零件。通過發(fā)動機臺架的初步試驗表明，所制備的粉末冶金TiAl基合金排氣閥表現(xiàn)出良好的服役性能。
關(guān)鍵字: 粉末冶金；TiAl基合金；柴油機；排氣閥；近型成形
（1. State Key Laboratory for Powder Metallurgy,
Central South University of Technology, Changsha 410083, P.R.China;
2. College of Material Science and Engineering, Harbin Institute of Technology, Harbin 150001, P.R.China）
Abstract:The manufacturing method and properties of P /M TiAl-based exhaust valves were investigated. The P/M TiAl-based exhaust valves were prepared through elemental powder metallurgy (EPM), i.e. elemental Ti, Al powders were used as raw material. Firstly, the mixed elemental powders were cold-pressed into a mushroomed head of the valve. Then the compacts were pseudo-HIPed, in which both the material synthesis and near net shaping were realized at one step. Finally, the P/M TiAl-based mushroomed valve heads were connected with the as-cast TiAl-based valve stems through diffusion joining technique. The primary results in diesel stand test using those valves prepared above showed that the diesel properties have met the requirements for practical application.
Key words: powder metallurgy; TiAl-based alloy; diesel exhaust valve; near net shaping
