Characterization of TiC and TiB2 reinforced Nickel Aluminide (NiAl) based metal matrix composites cast by in situ vacuum suction arc melting

• Published in: Vacuum Vol. 172; p. 109066
• Main Authors: Talaş, Şükrü, Oruç, Göksel
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2020
• Subjects: Metal matrix composites; Nickel aluminides; TiB2; TiC; Vacuum suction casting; Metal matrix composites; TiB2; Nickel aluminides; Vacuum suction casting; TiC
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2019.109066

The development of materials with high temperature performance are progressively increasing towards the new generation alloys for better wear and oxidation resistance, extending service life and economical production methods. In this study, in addition to NiAl, NiAl composites reinforced with TiC or TiB2 was produced and characterized. Ni, Al, TiC and TiB2 powders are compacted and subsequently remelted by vacuum suction arc melting at atmospheric pressure. TiC and TiB2 additions are in the range 0.5, 1, 2, 4 and 8 wt %. The samples were obtained in the form of bar and metallographic examination was made in order to characterize the specimens produced. The types of phases, microstructure and their hardness were investigated by XRD, Scanning Electron Microscope and microhardness test. Studies showed that all samples consisting of single-phase matrix and the TiC/TiB2 particles remain in most cases insoluble or re-formed in the matrix. Hardness values vary according to the amount of increasing second phase particles. Although both additions generate similar results in hardness, the microstructure of TiC reinforced samples resulted in the second phase structure with a spherical shape while TiB2 reinforced samples resulted in rod-like structure. Heat treated specimens showed a dramatic change in microstructural and physical properties. •TiC additions produced a spherical particles compared to rod-like structure with TiB2 additions.•Heat treatment of TiC/TiB2 +NiAl composites generated coarser precipitates with a corrugated edges and low hardness.•NiAl+8 wt% TiB2 produced a phase of Ni20Al3B6-12 in both as cast and heat treated composites.•Vacuum suction arc remelting is applicable to make composites of NiAl with additions TiC and TiB2.