(1. 西安理工大學 材料科學與工程學院，西安 710048；
2. 先進粉末冶金技術和新材料西安市重點實驗室，西安 710048)
摘 要: 以純Ti粉和TiB2粉為原料，采用放電等離子燒結技術制備原位自生Ti-TiBw復合材料，系統(tǒng)研究了熱處理條件對Ti-TiBw復合材料組織演變及力學性能的影響。結果表明：Ti和TiB2在1000 ℃燒結后原位反應生成了Ti-TiBw復合材料，TiBw主要以團簇狀分布于基體的一次顆粒邊界(PPBs)處，少量以針狀分布于晶界及晶內(nèi)。熱處理結果表明，溫度是TiBw發(fā)生粗化的主導因素，且TiBw粗化發(fā)生在升溫階段，粗化溫度為1200 ℃。其粗化行為遵循Ostwald熟化機制：為使體系自由能降低，溶質(zhì)B原子從小尺寸TiBw周圍向大尺寸TiBw周圍進行擴散并沉積，使得TiBw數(shù)量減少，對基體的割裂程度減弱，因此材料延性提高。
關鍵字: Ti-TiBw復合材料；熱處理；顯微組織；Ostwald熟化機制；力學性能
（1. School of Materials Science and Engineering, Xi''an University of Technology, Xi''an 710048, China;
2. Xi''an Key Laboratory of Advanced Powder Metallurgy Technology and New Materials, Xi''an 710048, China）
Abstract:The in-situ autogenerated Ti-TiBw composites were prepared by spark plasma sintering using pure Ti powder and TiB2 powder as raw materials. The effect of heat treatment conditions on the microstructure evolution and mechanical properties of Ti-TiBw composites were systematically studied. The results show that Ti-TiBw composites are synthesized in situ after sintering Ti and TiB2 at 1000 ℃. TiBw is mainly distributed in clusters at the primary particle boundary of the matrix, and a small amount of TiBw is distributed in the grain boundary and ingrain. The heat treatment results show that temperature is the dominant factor for TiBw coarsening, and TiBw coarsening occurs in the heating stage, and the coarsening temperature is 1200 ℃. The coarsening behavior follows the Ostwald ripening mechanism: To reduce the free energy of the system, solute B atoms diffused and deposited around small-size TiBw to large-size TiBw, reducing the amount of TiBw and weakening the degree of cleavage to the matrix, thus improving the ductility of the material.
Key words: Ti-TiBw composite material; heat treatment; microstructure; Ostwald ripening; mechanical properties
