Coordinately Improving the Wear and Fatigue Properties of Ti6Al4V Alloy by Designed CrZr-alloyed Layer

Abstract

A CrZr-alloyed layer was prepared through a pre-zirconizing and subsequent chromizing treatment on a Ti6Al4V substrate. After the removal of the top Cr deposit and Ti₄Cr layers, a (Cr,Zr)-Ti solid-solution layer was obtained. The microstructure, composition, microhardness and toughness of the (Cr,Zr)-Ti solid-solution layer were evaluated. The results showed that the pre-addition of Zr played an important role in inhibiting the precipitation of the soft Ti4Cr phase, which in turn allowed us to obtain a material characterized by a remarkable hardness. Wear and fatigue tests showed that the (Cr,Zr)-Ti solid-solution layer could coordinately improve the properties of the Ti6Al4V alloy. This was mainly due to the good match of hardness and toughness of the (Cr,Zr)-Ti solid-solution layer. In addition, the gradual change in composition and mechanical properties was conducive to the coordinated deformation between the (Cr,Zr)-Ti solid-solution layer and the Ti6Al4V substrate during fatigue tests. This reduced the stress concentration in correspondence of the interface between the two materials.

Keywords

Ti6Al4V alloy / surface alloying / wear / fatigue / hardness and toughness

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