Interfacial Microstructure and Mechanical Properties of Titanium/Sapphire Joints Brazed with AuSn20 Filler Metal

Abstract

In this study, C-plane (0001) sapphire was successfully brazed to titanium using AuSn20 filler metal, following metallization on the surface of the sapphire with Sn-3Ti (wt.%). At 1000 °C, Sn-3Ti had good wettability on the surface of the sapphire, with the lowest equilibrium contact angle of 57°. The reaction phases in the joints were identified, and the typical interfacial microstructure of the brazed joint brazed at 550 °C for 30 min was titanium substrate/Au-Sn-Ti layer/Ti6Sn5 + AuSn2 + AuSn4 + massive Au-Sn-Ti/TiO phase/sapphire. The shear test was utilized to evaluate the bonding strength of the titanium/sapphire joints. The highest shear strength reached 18.7 MPa when brazed at 550 °C for 35 min. The crack was initiated at the sapphire/brazing seam interface and propagated into the Au-Sn-Ti reaction layer.

Manufacturing of Sapphire Crystals with Variable Shapes for Cryosurgical Applications

“…First of all, it demonstrates biocompatibility and chemical inertness, that allows for the direct contact of sapphire windows and probes with biological tissues and liquids [4,5]. Outstanding mechanical properties, such as high hardness, enable the development of sapphire medical instruments and bone implants [6,7]. Transparency in visible and near infrared ranges provides an ability to light delivering to tissues, which has been recently used for the development of concepts of optically-based sapphire multimodal instruments for tissue ablation, resection, diagnosis and therapy [8,9].…”