Study on Hot Rolling Process and Microstructure and Properties of Ti-6Al-4V/TiAl Clad Plate under Large Reduction

Ti-6Al-4V(wt%)/ Ti-43Al- 3V-2Cr(at%) composite clad plate without interfacial defects was successfully prepared by a high-reduction hot-rolling method. Microstructure and mechanical properties were studied. The experimental results show that no obvious defects in the interfacial region is observed, and the Kirkendall phenomenon is successfully avoided. The interface thickness of the composite plate is about 230 mu m, according to different phase compositions, the interface is divided into two regions, one of which is the interface near Ti-6Al- 4V alloy and is mainly composed of alpha/alpha(2)+beta/B2 phases; region 2 is the interface near TiAl alloy, and mainly consists of alpha/alpha(2)+beta/B2+gamma phases. The forming of interface region structure is due to the diffusion of Ti element from Ti-6Al-4V alloy to TiAl alloy layer and the diffusion of Al and Cr elements from TiAl layer to Ti-6Al-4V layer. The Vickers hardness and three-point flexural resistant strength of the composite panels were tested. The experimental results show that the interface region 1 has the highest microhardness, and the composite plate exhibits the best bending resistance when the surface of the transverse specimen was loaded, and the bending strength reaches 1150.82 MPa. The bending fractures of the alloy layers and interfacial region are brittle fractures, there is no cracking in the interfacial region.