A yttrium-containing high-temperature titanium alloy additively manufactured by selective electron beam melting

摘要

A yttrium-containing high-temperature titanium alloy（Ti-6Al-2.7Sn-4Zr-0.4Mo-0.45Si-0.1Y, mass fraction, %） has been additively manufactured using selective electron beam melting（SEBM）. The resulting microstructure and textures were studied using scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD） and electron backscattered diffraction（EBSD） and compared with the conventionally manufactured form. A notable distinct difference of microstructures is that additive manufacturing by SEBM enables homogeneous precipitation of fine Y2O3 dispersoids in the size range of 50-250 nm throughout the as-fabricated alloy, despite the presence of just trace levels of oxygen（7×10-4, mass fraction） and yttrium（10-3, mass fraction） in the alloy. In contrast, the conventionally manufactured alloy shows inhomogeneously distributed coarse Y2O3 precipitates, including cracked or debonded Y2O3 particles.