ICALEO 2005 Paper #1106 (Synthesis of Nb3Al High Temperature Intermetallic Compound by Laser Deposition)
Minlin Zhong, Tsinghua University; Beijing China
Jinjiang He, Tsinghua University; Beijing China
Wenjin Liu, Tsinghua University; Beijing China
Presented at ICALEO 2005
Refractory intermetallic compound Nb3Al is expected as a candidate for structural materials operated at much higher temperatures compared to conventional Ni superalloys. However, Nb3Al is difficult to fabricate by conventional methods. Little work has been reported on synthesis of Nb-rich intermetallic alloys by laser deposition. This paper presents research work on laser deposition of a powder blend of Nb, Ti, Al pure elements to form Nb3Al intermetallic compound. The research focuses on an alloy composition of Nb?12Ti?22Al (at.%) with a d-Nb3Al phase based on Nb-Ti-Al ternary phase diagram at 1473K. A single Nb3Al phase intermetallic layer with a composition close to the atom ratios of the elemental powder blend was obtained by laser deposition in an argon atmosphere chamber. The microstructure characterization and phase identification were analyzed by SEM, XRD. The Nb3Al intermetallic compound is fine and homogeneous in the deposited layers. The effect of processing parameters on the microstructure and the synthesizing mechanics were discussed. A critical laser deposited height of Nb3Al intermetallic layers free of cracks was tested.