【作者】 李敏；

【导师】 李世春；

【作者基本信息】 中国石油大学 ， 材料加工工程， 2008， 硕士

【摘要】 扩散连接中,相界面的迁移由界面处原子的扩散与溶解情况来决定。因此,对异相界面上原子的扩散研究就显得十分重要。本文选择Ti-Ni-Cu三元扩散偶以及扩散偶中的Ti-Cu、Ti-Ni和Cu-Ni二元界面来研究界面行为。实验采用铆钉法制备扩散偶试样,经过一定条件的退火热处理后,扩散偶组元界面由原始的机械接触转变成冶金结合,在界面区域形成了不同于基体的扩散层。利用光学金相和SEM背散射技术对扩散偶界面区域特征进行了分析,结果表明:由于三元扩散偶制作工艺上的特点,同一扩散偶两个三结点区域生成的扩散层形貌并不完全相同。利用电子探针微区成分分析技术,对三元扩散偶中扩散层内各亚层相进行了分析,结合三元相图并辅以热力学计算,发现Ti-Ni-Cu三元扩散偶经过700℃200h退火热处理后,在三结点区域有三元金属间化合物和二元金属间化合物同时生成。三结点区域亚层相分布:Ti在-Ni界面由Ti向Ni依次为Ti2Ni、TiNi、CuNi3Ti2和TiNi3;在Ti-Cu界面由Ti向Ni依次为Ti2Cu+α-Ti、TiCu、Ti3Cu4、TiCu2和TiCu4;三结点处为三元相Ti(Ni,Cu)相区。扩散偶热处理后远离三结点的Ti-Cu和Ti-Ni界面区域生成的扩散层与基体之间界面清晰、规则;Cu-Ni界面生成的扩散层与基体之间没有清晰的界面,这是因为热处理后,前者生成的是金属间化合物,后者生成的是固溶体。金属间化合物与基体间界面清晰,是因为在界面两侧发生了成分突变。在分析二元系界面特征时还发现,实验工艺参数对扩散层有较为重要的影响。温度越高,扩散层厚度越厚,两者符合指数关系;退火时间越长,扩散层厚度越厚,两者呈抛物线关系。对二元界面区域扩散层内各亚层相进行分析时发现,各相生成顺序不仅与其生成焓有关,而且与界面上原子浓度也有很大关系。更多还原

【Abstract】 The migration of phase interface in diffusion bonding is up to the diffusion anddissolution of atoms at the interface, so it is very important to research the diffusion of atomsat different phase interface. The Ti-Ni-Cu diffusion triple specimens were made by rivetingmethod to research the interface behavior. After a series of heat treatment under differentconditions, diffusion zones between the components are formed from the compact contact ofthe bulks of the components. The microstructure characteristics of the diffusion zones werestudied by means of optical metallography and SEM backscattering technique. The resultsshow that the diffusion phenomena at triple points in the specimens are affected by themechanical technics of preparing specimens. With the help of the X-ray PhotoelectronSpectroscopy, phase diagram as well as thermaodynamics calculation, it has been shown thatthere are binary and ternary intermetallic compounds simultaneously near the triple crunodewhen the Ti-Ni-Cu diffusion triple are annealed at 700℃for 200 hours. There are fourintermetallic compounds at Ti-Ni interface, and their arrangement from Ti to Ni isTi2Ni,TiNi,CuNi3Ti2 and TiNi 3.There are five intermetallic compounds at Ti-Cu interface andtheir arrangement from Ti to Cu is Ti2Cu+α-Ti,TiCu,Ti3Cu4,TiCu2 and TiCu4. There is aTiNiCu at the triple crunode.The interfaces between diffusion layers and matrix are regular and clear at Ti-Cu and Ti-Ni interfaces, and there are 3 intermetallic phases in Ti-Ni interface while 6 intermetallicphases in Ti-Cu interface when the Ti-Ni-Cu diffusion triple specimens are annealed at 700℃for 200 hours. The interfaces between diffusion layers and matrix are vague at Cu-Niinterface far away from the triple crunode, and there are solid solution in this zone. It hasbeen seen that the diffusion layers become thick when the temperature is high, which allowsexponential relationship, and the diffusion layers become thick when the annealing time islong, which allows a parabolic relationship. The inborn order of the phases in the diffusionlayers is not only influenced by the heat of formation, but also by the concentration of atomsat the interfaces.更多还原