Phase formation and kinetics in melt-spun and sputtered alloys along the line Cu40Ni60Cu30Ni45Sn25

Abstract

The ternary system CuNiSn includes intermetallic phases of DO19, 2H and DO3 structure. These have some interesting properties for future mechanical investigations. Recently, CuNiSn alloys were investigated to understand the process of phase formation and to learn how to produce single-phase and well defined multi-phase material. The results show complex phase formation and leave some open questions, especially concerning the low-temperature range. The present investigation uses sputtered and melt-spun CuNiSn alloys to get information about the influence of different preparation methods. Isothermal and dynamic X-ray diffraction measurements together with TEM investigations reveal information about the phase diagram and kinetics of phase formation down to 500 °C. Proposed equilibrium diagrams are presented: a vertical section along Cu40Ni60Cu30Ni45Sn25 and isothermal cuts across the Sn-poor side of the ternary CuNiSn diagram. The precipitation of intermetallic phases in supersaturated ternary solid solutions is shown to be a two-step process.