Microstructural Evolution and Mechanical Properties of an Advanced γ-TiAl Based Alloy Processed by Spark Plasma Sintering

Materials

Svea Mayer¹  David Wimler¹  Helmut Clemens¹  Janny Lindemann² 

[1] Department of Materials Science, Montanuniversität Leoben, 8700 Leoben, Austria;GfE Fremat GmbH, 09618 Brand-Erbisdorf, Germany;

关键词: spark plasma sintering;    γ-TiAl based alloys;    TNM alloy;    heat treatment;    mechanical properties;   

DOI  :  10.3390/ma12091523

来源: DOAJ

【 摘 要 】

Intermetallic γ-TiAl based alloys are innovative lightweight structural high-temperature materials used in aerospace and automotive applications due to already established industrial-scale processing routes, like casting and hot-working, i.e., forging. A promising alternative method of production, regarding manufacturing of near net-shape components, goes over the powder metallurgy route, more precisely by densification of TiAl powder via spark plasma sintering. In this study, gas atomized powder from the 4th generation TNM alloy, Ti-43.5Al-4Nb-1Mo-0.1B (in at.%), was densified and the microstructure was investigated by means of electron microscopy and X-ray diffraction. The sintered microstructure exhibits lamellar α₂-Ti₃Al /γ-TiAl colonies surrounded by globular γ- and ordered β_o-TiAl phase. The coarse lamellar spacing stems from the low cooling rate after densification at sintering temperature. Against this background, subsequent heat treatments were designed to decrease the lamellar widths by a factor of ten. Accompanying, tensile tests and creep experiments at different temperatures revealed that the modified almost fully lamellar microstructure is enhanced in strength and creep resistance, where a small volume fraction of globular γ-phase provides ductility at ambient temperatures.

【 授权许可】

Unknown