Wear characteristics of PVD coated carbide tools in milling of TA15 titanium alloy

Abstract

Titanium alloy, due to its small elastic modulus and poor thermal conductivity, is easy to exacerbate tool wear during milling which affects its machinability. In this work, an experimental investigation was conducted to analyze the effect of the properties and microstructure of different coatings on tool wear behavior and machining stability during the milling process of TA15 titanium alloy. Physical vapor deposition technology was applied to prepare AlTiSiN and AlZrTiN coatings on carbide samples, respectively, and their microstructures and mechanical properties were investigated. The results showed that AlZrTiN coating exhibited a higher elastic modulus, indicating that it had better resistance to peel off than AlTiSiN coating. Moreover, milling experiments were performed with AlTiSiN and AlZrTiN coated tools to investigate wear characteristics and mechanism. When milling TA15, the two coated tools mainly suffered adhesive wear and oxidation wear. AlZrTiN coated tool exhibited a better wear resistance during long time milling. The surface roughness of TA15 obtained by AlZrTiN coated tool was better than that by AlTiSiN coated tool, achieving approximately Ra0.089 µm. As a result, AlZrTiN coated tool exhibits a better cutting characteristic and is preferred for milling of TA15 titanium alloy.