ALTI INTERMETALLIC COMPOUND HAVING HIGH TOUGHNESS, HIGH DUCTILITY, AND HIGH STRENGTH

摘要

PURPOSE:To obtain the AlTi intermetallic compound by forming a metallic structure into a dual phase structure consisting of respectively specified first phase and second phase and specifying the volume fraction of the second phase. CONSTITUTION:This AlTi intermetallic compound has a first phase where a first additive element (a) consisting of Cr and/or Mn is incorporated into an Al3Ti phase and a second phase consisting of Al3Ti phase and/or AlTi-r phase, and further, the volume fraction Vf of the second phase is regulated to 0.01-70%. Moreover, this intermetallic compound has a composition consisting of, by atom, 25-50% Ti, 0.01-15% element (a), and the balance Al. Because the element (a) is preferentially substituted by Al and contributes toward modifying the crystalline structure of the Al3Ti phase owing to the above constitution, the toughness and ductility of the first phase can be improved and, as a result, the development of cracks can be inhibited by the second phase having hardness, toughness, and ductility higher than those of the first phase even if cracks occur in the first phase. The crack development inhibiting effect cannot be obtained when Vf is 0.01%, and, when it is 70%, high temp. characteristics, particularly, high temp. oxidation resistance inherent in the AlTi intermetallic compound is inhibited.