(1. 上海電力學(xué)院 能源與機械學(xué)院，上海 200090；
2. 上海交通大學(xué) 激光制造與材料改性重點實驗室，上海 200240)
摘 要: 在Ti-3Al-2V表面激光熔覆原位合成TiB/TiN復(fù)合強化鈦基復(fù)合涂層。采用XRD、SEM、EPMA和TEM等方法分析原位合成強化顆粒的顯微形貌和生長方式。結(jié)果表明：熔覆層中存在兩種原位合成強化相TiB和TiN；面心立方結(jié)構(gòu)的TiN具有較高的各向同性，在快速凝固條件下呈現(xiàn)樹枝晶和等軸晶形貌；TiB具有兩種形態(tài)，初生TiB具有空心結(jié)構(gòu)針棒狀TiB，空心結(jié)構(gòu)內(nèi)部孔洞不規(guī)則，各處壁厚不均勻；共晶的TiB呈現(xiàn)細(xì)小、實心的針棒狀組織形貌。TiB為B27結(jié)構(gòu)，點陣常數(shù)為α=0.628 nm，b=0.312 nm和c=0.461 nm；TiB沿[0 1 0]方向的生長速度最快，堆垛層錯的方向平行于(1 0 0)面，并且伴隨位錯的產(chǎn)生。
關(guān)鍵字: 激光熔覆；原位合成強化顆粒；TiB；TiN；結(jié)晶
（1. Shanghai Engineering Research Center of Power Generation Environment Protection,
Shanghai University of Electric Power, Shanghai 200090, China;
2. Shanghai Key Laboratory of Materials Laser Processing and Modification,
Shanghai Jiao Tong University, Shanghai 200240, China）
Abstract:In-situ synthesized TiN and TiB reinforced titanium matrix composites were fabricated on surface of Ti-3Al-2V alloy by laser cladding. The coating were evaluated and characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), electron probe microanalyzer (EPMA) and transmission electron microscopy (TEM). The results show that there are two in-situ synthesized reinforced phases in the coating TiN and TiB. The high isotropic structure and high cooling speed of laser cladding lead to TiN with dendrite/equiaxed grains. TiB shows two different shapes, little primary TiB shows coarse needle platelet with hollow shape, the hollow structure is not regular and the wall thickness is different. The eutectic TiB shows fine solid needle platelet. TiB is B27 structure with lattice constants a=0.628 nm, b=0.312 nm and c=0.461 nm. TiB grows fast in the direction of [0 1 0]. The stacking fault is parallel to (100) and it is accompany with the generation of dislocation.
Key words: laser cladding; in-situ synthesized reinforced phase; TiB; TiN; crystallization
