Microstructure transformed by heat treatment to improve fatigue property of laser solid formed Ti6Al4V titanium alloy

Additive manufacturing (AM) can manufacture near-net-shape metal parts with complex geometries, but their fatigue performance limits wide application. In this work, the heat treatment was optimized to change microstructure to improve fatigue performance of laser solid formed Ti6Al4V alloys. After heat treatment at 800 °C for 4 h, the distribution of α plate transformed from colony to basket-weave, and the fatigue limit increased from 203 MPa to 225 MPa at a stress ratio of 0.1. The results showed that the basket-weave structure affected the original texture of the colony and changed the fatigue crack propagation path. This effectively improved the fatigue life to expand the application potential of additive manufacturing parts.