PROBLEM TO BE SOLVED: To provide a NiTi-based alloy material excellent in fatigue resistance by properly controlling contents of carbon and oxygen in the NiTi-based alloy and controlling a generation phase of an inclusion by high frequency vacuum fusion or arc melting used on a commercial scale, and to provide a wire or pipe material containing the same.SOLUTION: Provided is a NiTi-based superelastic alloy material or a shape memory alloy material, in which carbon density is less than 0.05 mass%, oxygen density is less than 0.05 mass%, a ratio of the carbon density to the oxygen density is carbon density/oxygen density≥1.5, an inclusion included in the material is a TiC single phase, and a fatigue limit is equal to or more than 480 MPa. A wire or pipe material containing the same is also provided.SELECTED DRAWING: NoneCOPYRIGHT: (C)2016,JPO&INPIT【課題】商業規模で用いられる高周波真空溶解やアーク溶解で、NiTi系合金中の炭素と酸素の含有量を適正に制御し、介在物の生成相を制御することで、耐疲労特性に優れたNiTi系合金材料及びこれを用いた線材または管材を提供する。【解決手段】NiTi系超弾性合金材料または形状記憶合金材料であって、炭素濃度が0.05質量%未満、酸素濃度が0.05質量%未満であって、炭素濃度と酸素濃度の比が炭素濃度/酸素濃度≧1.5であって、材料中に含まれる介在物がTiC単相であって、疲労限が480MPa以上である、NiTi系超弾性合金材料または形状記憶合金材料及びこれを用いた線材または管材。【選択図】なし
