TiZrNiCu/Ti60润湿性及与TiBw-TC4钎焊研究

Wettability of TiZrNiCu-B/Ti60 system and its brazing to TiBw-TC4 composite

摘要:

本文采用座滴法在真空下系统研究了硼含量对TiZrNiCu/Ti60润湿性的影响,且在940°C保温10分钟条件下实现了与的钎焊。通过SEM、XRD以及剪切实验研究了界面显微组织及剪切力学性能。添加B元素可以与Ti原位合成TiBw,从而细化界面的显微组织。当B含量为0.3 wt %时,TiBw-TC4 /TiZrNiCu-B/Ti60接头的最大剪切强度为177 MPa,比无B含量的接头强度高65%。然而,过量的B含量使TiZrNiCu-B在Ti60合金基体上产生大量的TiBw,导致润湿性恶化,在钎焊接头形成微孔和未焊合区域,从而使剪切强度下降。

Abstract:

In this work, the connection between the boron content and the wettability of TiZrNiCu/Ti60 system was studied by sessile drop method of elevating and maintaining isothermal process under vacuum, and TiBw-TC4 composite was successfully brazed to Ti60 alloy using TiZrNiCu-B filler alloy with brazing temperature of 940 °C for 10 min. The contact angle of TiZrNiCu/Ti60 alloy substrate and the corresponding interfacial microstructure, the interfacial microstructures and shear fractures of brazed joints were studied using SEM, EDS and XRD, and the influence of B content on interfacial microstructure and joining properties was also investigated in detail. Added B element can react with Ti to in-situ synthesizing TiB whiskers (TiB_w), which resulted in a relative refinement of microstructure. And the maximum shear strength of TiBw-TC4/TiZrNiCu-B/Ti60 joint was 177 MPa when the content of B is 0.3 wt.%, which was 65% higher than the joints brazed without B content. However, the excessive B content worsened the wetting behavior of TiZrNiCu-B on Ti60 alloy substrate, resulted in the microvoids and disconnected area in the brazed joint, and the shear strength decreased inevitably.