The Effect of Scan Pattern on Microstructure Evolution and Mechanical Properties in Electron Beam Melting Ti47Al2Cr2Nb

Ti47Al2Cr2Nb alloy square samples with dimensions of 20mm x 20mm x 5mm were fabricated by electron beam selective melting. In order to study the effect of electron beam scan pattern on the microstructure evolution, three different scan patterns were employed: S-shaped scan line, Z-shaped scan line and interlayer orthogonal S-shaped scan line. Microstructural and chemical analyses were conducted using optical microscopy, scanning electron microscopy and energy differential system. It is worth noting that the element Al loss rate was about 8% under different process parameters. As a result, the microstructures of EBSM Ti47Al2Cr2Nb samples were composed of columnar β grains, α/α2and α2/γ lamellar. Tensile tests were carried out to understand the mechanical properties to the corresponding microstructures. Ultimate Tensile Stress (UTS)at room temperature is much lower than that at a high temperature.