Yue Gui-Lin, Chen Tai-Cheng, Shiue Ren-Kae, Tsay Leu-Wen
Doctoral Degree Program in Ocean Engineering Technology, National Taiwan Ocean University, Keelung 202301, Taiwan.
Engineering Training Center, Jiangsu Ocean University, Lianyungang 222005, China.
Materials (Basel). 2021 Oct 10;14(20):5949. doi: 10.3390/ma14205949.
Dissimilar brazing of Ti-15Mo-5Zr-3Al (Ti-1553) to commercially pure titanium (CP-Ti) using Ti-15Cu-15Ni foil was performed in this work. The microstructures in different sites of the brazed joint showed distinct morphologies, which resulted from the distributions of Mo, Cu, and Ni. In the brazed zone adhered to the Ti-1553 substrate, the partitioning of Mo from the Ti-1553 into the molten braze caused the formation of stabilized β-Ti without TiCu/TiNi precipitates. In the CP-Ti side, the brazed joint displayed a predominantly lamellar structure, composed of the elongated primary α-Ti and β-transformed eutectoid. The decrease in the Mo concentration in the brazed zone caused the eutectoid transformation of β-Ti to TiCu + α-Ti in that zone. The diffusion of Cu and Ni from the molten braze into the CP-Ti accounted for the precipitation of TiCu/TiNi in the transformed zone therein. The variation in the shear strength of the joints was related to the amount and distribution of brittle TiNi compounds. Prolonging the brazing time, the wider transformed zone, consisting of coarse elongated CP-Ti interspersed with sparse TiNi precipitates, was responsible for the improved shear strength of the joint.
在本工作中，使用Ti-15Cu-15Ni箔对Ti-15Mo-5Zr-3Al（Ti-1553）与工业纯钛（CP-Ti）进行了异种钎焊。钎焊接头不同部位的微观结构呈现出明显的形态，这是由Mo、Cu和Ni的分布所致。在与Ti-1553基体相连的钎焊区，Mo从Ti-1553向熔化的钎料中偏析，导致形成了无TiCu/TiNi析出物的稳定β-Ti。在CP-Ti一侧，钎焊接头呈现出以层状结构为主，由拉长的初生α-Ti和β转变共析体组成。钎焊区中Mo浓度的降低导致该区域β-Ti向TiCu + α-Ti的共析转变。Cu和Ni从熔化的钎料扩散到CP-Ti中，导致在其中的转变区析出TiCu/TiNi。接头剪切强度的变化与脆性TiNi化合物的数量和分布有关。延长钎焊时间，由粗大拉长的CP-Ti夹杂稀疏TiNi析出物组成的更宽转变区，是接头剪切强度提高的原因。
