以氢化钛(TiH2)粉代替钛粉,与氮化铝(AlN)粉体混合,合成高纯的三元氮化物Ti2AlN陶瓷粉体。氢化钛与氮化铝按照摩尔比2∶1的配比,在混料机中混合12 h,然后放入流动氩气气氛保护的管式炉中高温处理。通过对在不同温度以及不同时间下进行...以氢化钛(TiH2)粉代替钛粉,与氮化铝(AlN)粉体混合,合成高纯的三元氮化物Ti2AlN陶瓷粉体。氢化钛与氮化铝按照摩尔比2∶1的配比,在混料机中混合12 h,然后放入流动氩气气氛保护的管式炉中高温处理。通过对在不同温度以及不同时间下进行热处理得到的产物进行物相分析,探究Ti2AlN的形成机理,发现在1400℃下保温2 h得到的Ti2AlN粉体纯度最高,约为96.2%(质量分数)。在同样条件下,以钛粉为钛源合成Ti2AlN粉体的纯度只有80.2%(质量分数)。因为氢化钛粉体价格低于钛粉,并且合成的样品纯度显著提高。所以,以氢化钛粉代替钛粉为钛源,合成Ti2AlN具有显著优势。同时研究了所合成Ti2AlN粉体在不同酸溶液(KF-HCl、NaF-HCl和NH4F-HCl)腐蚀行为。结果发现:将Ti2AlN(~2 g)浸入由2 g KF溶解在40 mL 6 M HCl的KF-HCl混合液中,在50℃下搅拌48 h得到碎片团簇型TiN。但是二维碳化物Ti2N MXene不能通过选择性刻蚀Ti2AlN的方法得到。展开更多
Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃...Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃ for 24 h after being heat treated at 1400 ℃ for 0.5 h. The in-situ composites consist of γ＋α2 lamellar colonies, equiaxed y grains and Ti2AlN reinforcements. Matrix with nearly fully lamellar structure formed after solution and subsequently aging treatment. With the increase of Ti2AlN content, the nearly fully lamellar structure becomes instable for the aged composites. According to TEM study, fine Ti2AlN precipitates are found to distribute at the grain boundaries of lamellar colony. Needle-like Ti3AlN precipitates arrange in line with growing axis parallel to [001] direction of the γ-TiAl matrix and another needle-like Ti3AlN precipitates with lager size distribute at the dislocations. Key words：展开更多
Microstructure stability of in situ synthesized Ti2AlN/Ti-48Al-2Cr-2Nb composite during aging at 900 ℃ was investigated by XRD, OM and TEM, and the unreinforced Ti-48Al-2Cr-2Nb alloy was also examined for comparison....Microstructure stability of in situ synthesized Ti2AlN/Ti-48Al-2Cr-2Nb composite during aging at 900 ℃ was investigated by XRD, OM and TEM, and the unreinforced Ti-48Al-2Cr-2Nb alloy was also examined for comparison. The result showed that in the TiAl alloy,α2 lamellae thinned and were broken down, and became discontinuous with increasing aging time. The decomposition ofα2 lamella toγ which was characterized by parallel decomposition and breakdown ofα2 lamellae led to the degradation of the lamellar structure. While in the composite, lamellar structure remained relatively stable even after aging at 900 ℃ for 100 h. No breakdown ofα2 lamellae except parallel decomposition and precipitation of fine nitride particles was observed. The better microstructural stability of the composite was mainly attributed to the precipitation of Ti2AlN particles at theα2/γ interface which played an important role in retarding the coarsening of lamellar microstructure in the matrix of composite.展开更多
文摘以氢化钛(TiH2)粉代替钛粉,与氮化铝(AlN)粉体混合,合成高纯的三元氮化物Ti2AlN陶瓷粉体。氢化钛与氮化铝按照摩尔比2∶1的配比,在混料机中混合12 h,然后放入流动氩气气氛保护的管式炉中高温处理。通过对在不同温度以及不同时间下进行热处理得到的产物进行物相分析,探究Ti2AlN的形成机理,发现在1400℃下保温2 h得到的Ti2AlN粉体纯度最高,约为96.2%(质量分数)。在同样条件下,以钛粉为钛源合成Ti2AlN粉体的纯度只有80.2%(质量分数)。因为氢化钛粉体价格低于钛粉,并且合成的样品纯度显著提高。所以,以氢化钛粉代替钛粉为钛源,合成Ti2AlN具有显著优势。同时研究了所合成Ti2AlN粉体在不同酸溶液(KF-HCl、NaF-HCl和NH4F-HCl)腐蚀行为。结果发现:将Ti2AlN(~2 g)浸入由2 g KF溶解在40 mL 6 M HCl的KF-HCl混合液中,在50℃下搅拌48 h得到碎片团簇型TiN。但是二维碳化物Ti2N MXene不能通过选择性刻蚀Ti2AlN的方法得到。
基金Project(2011CB605502)supported by the National Basic Research Program of ChinaProject(51001086)supported by the National Natural Science Foundation of China
文摘Microstructures of Ti2AlN/TiAl composites prepared by in-situ method were characterized in in-situ and aging treatment conditions and the nitride precipitation was investigated in Ti2AlN/TiAl composites aged at 900 ℃ for 24 h after being heat treated at 1400 ℃ for 0.5 h. The in-situ composites consist of γ＋α2 lamellar colonies, equiaxed y grains and Ti2AlN reinforcements. Matrix with nearly fully lamellar structure formed after solution and subsequently aging treatment. With the increase of Ti2AlN content, the nearly fully lamellar structure becomes instable for the aged composites. According to TEM study, fine Ti2AlN precipitates are found to distribute at the grain boundaries of lamellar colony. Needle-like Ti3AlN precipitates arrange in line with growing axis parallel to [001] direction of the γ-TiAl matrix and another needle-like Ti3AlN precipitates with lager size distribute at the dislocations. Key words：
基金Project(2011CB605502)supported by the National Basic Research Program of ChinaProject(B08040)supported by Introducing Talents of Discipline to Universities,China
文摘Microstructure stability of in situ synthesized Ti2AlN/Ti-48Al-2Cr-2Nb composite during aging at 900 ℃ was investigated by XRD, OM and TEM, and the unreinforced Ti-48Al-2Cr-2Nb alloy was also examined for comparison. The result showed that in the TiAl alloy,α2 lamellae thinned and were broken down, and became discontinuous with increasing aging time. The decomposition ofα2 lamella toγ which was characterized by parallel decomposition and breakdown ofα2 lamellae led to the degradation of the lamellar structure. While in the composite, lamellar structure remained relatively stable even after aging at 900 ℃ for 100 h. No breakdown ofα2 lamellae except parallel decomposition and precipitation of fine nitride particles was observed. The better microstructural stability of the composite was mainly attributed to the precipitation of Ti2AlN particles at theα2/γ interface which played an important role in retarding the coarsening of lamellar microstructure in the matrix of composite.
