Regularities of the formation of the polymetallic samples of the Fe-Ti, Fe-Cu-Ti system, produced by the wire-feed electron beam additive manufacturing

Abstract

The results of structural studies of the bimetallic samples Fe-Ti system and the polymetallic samples Fe-Cu-Ti system produced by the wire-feed electron beam additive manufacturing are presented. It was found that for the Fe-Ti bimetal in the additive part of the Add Ti-6Al-4V titanium alloy there are a large number of cracks, delamination and microcracks. This is due to the formation of brittle FeTi and Fe2Ti intermetallic compounds. Growth of intermetallides and their subsequent deformation in the process lead to material destruction. To solve the problem of embrittlement of the workpiece, two copper layers of Add C11000 were introduced during the manufacturing process between steel and titanium parts of Add SS 321-Add Ti-6Al-4V. Thus, for Fe-Cu-Ti polymetal, the dominant phase on the boundary Add C110000-Add Ti-6Al-4V area is intermetallic CuTi2. Cracks are interrupted when encountered with the Cu solid solution, which suggests a positive effect of Cu on containing the crack propagation. Microcracks observed in Add Ti-6Al-4V do not propagate further in the Cu + CuTi2 region, which indicates a lower cracking tendency of intermetallic phases of CuTi2 in comparison with FeTi and Fe2Ti intermetallics. Experimental studies have confirmed and showed that the use of an additional layer between different components in the wire-feed electron beam additive manufacturing also helps to produce a quality defect-free product from heterogeneous materials.