Formations of amorphous and quasicrystal phases in Ti–Zr–Ni–Cu alloys

• Published in: Journal of alloys and compounds 2003-10, Vol.361 (1), p.234-240
• Main Authors: Wang, Limin, Ma, Liqun, Ma, Chaoli, Inoue, Akihisa
• Format: Article
• Language: English
• Subjects: Amorphous; Casting; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Icosahedral quasicrystal; Microstructure; Physics; Quasicrystals; Rapid solidification; Semi-periodic solids; Structure of solids and liquids; crystallography; Ti–Zr–Ni–Cu alloy
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/S0925-8388(03)00430-4

The structure of melt-spun Ti 45Zr 35Ni 20− x Cu x ( x=0, 1, 3, 5 and 7) alloys and a cast Ti 45Zr 35Ni 17Cu 3 bulk alloy have been studied. The melt-spun alloys have different structures depending on the thickness of the melt-spun ribbons. When the thickness is 86±5 μm, icosahedral quasicrystal (I) and Laves (L) phases are formed for x=0 and 7, and a single I phase is formed for x=1, 3 and 5. When the thickness decreases to 20±2 μm, I and amorphous phases are formed for x=0 and 1, and a single amorphous phase is formed for x=3, 5 and 7. The thickness of 15±1 μm for x=0 and 1 also causes the formation of a single amorphous phase. The cast alloy also has different structures depending on the size of the bulk samples. The structure of the cast rod sample with a diameter ( D) of 1 mm consists mainly of I and amorphous phases. The I phase is homogenously distributed and its particle size is less than 5 μm. I and C14 L phases are formed in the cast rod sample with D of 2 mm. The particle size of the I phase is less than 10 μm. The volume fraction ( V f) of the I phase is about 67% for D of 1 mm rod and 55% for D of 2 mm rod. Three phases of I phase, C14 L and β-(Ti,Zr) are formed in the cast rod sample with D of 3 mm. EDS measurement indicates that the I phase has an approximate composition of Ti 49Zr 36Ni 13Cu 2.