PSI - Issue 2_A

L.L. Meisner et al. / Procedia Structural Integrity 2 (2016) 1465–1472 L.L. Meisner et al./ Structural Integrity Procedia 00 (2016) 000 – 000

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different inclusions are observed: TiC(O) or TiC x O y inclusions, containing significant amount of oxygen; Ti 4 Ni 2 C x O y inclusions, as well as the duplex TiC x O y +Ti 4 Ni 2 C x O y and/or TiC+Ti 4 Ni 2 O x inclusions. In the precision TiNi alloy the main type of inclusions is oxide Ti 4 Ni 2 O x . 2. In the experiments on both TiNi alloys, exposed to single-pulse LEHCEB-treatment, it was found that microcraters arise upon reaching the surface melting threshold of B2 matrix phase. It was found by OM and SEM/EDS methods that the sites of microcraters are mainly TiC(O) (commercial alloy) and Ti 4 Ni 2 O (precision alloy) inclusions. 3. Three types of microcraters were identified by OM and laser profilometry: (1) “dimple - rim”; (2) “dimple - rim” with conical inclusion residue; (3) “dimp le- rim” with quasi -flat bottom. It has been shown that microcraters of types 1 and 2 are formed on TiC(O) inclusions, while the nucleation sites of microcraters of type 3 are Ti 4 Ni 2 O x inclusions. In all three types of microcraters, high concentration of oxygen was observed, which decreases rapidly from the center to the periphery.

Acknowledgements

This work was funded by Russian Science Foundation (project No. 15-13-00023).

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