Additive manufacturing of gamma titanium aluminide alloys: a review

Titanium aluminide (TiAl) is an attractive alloy, especially in the aviation and automotive industry, due to its good corrosion and oxidation resistance, low density, high specific strength, and creep properties. Among TiAl alloys, gamma-TiAl, which can maintain its mechanical properties at high temperatures, has the most common use. However, it is difficult to produce by conventional methods due to its high reactivity and brittle behavior at room temperature. Due to these difficulties, additive manufacturing (AM) of gamma TiAl has started to come to the fore with the development of AM in recent years. Although it has a relatively higher cost, AM preference is increasing day by day due to the process characteristics it exhibits during production, low buy-to-fly ratio, no shape limitation, and relatively short transition time from technical drawing to part. This paper provides a detailed review of publications on the manufacture of parts with gamma-TiAl alloys by AM methods. This review addresses recent findings on the topic, the challenges, and ways to improve shortcomings of the AM methods. The necessary conditions for the desired products are explained by referring to feedstock material preparation techniques and process parameters. The comparison of AM methods in terms of microstructure characteristics, defects, and mechanical properties is discussed. As a result, shortcomings encountered in production can be improved by the optimization of process parameters for all AM methods.