The Effect of Cu-Macroalloying Additions to Rapidly Solidified NiAl Intermetallic Compound

Abstract

ABSTRACTThe effects of two variables on the NiAl intermetallic compound were studied: 1) copper macroalloying additions and 2) rapid solidification processing. For that purpose, several NiCuAl alloys were vacuum induction melted and rapidly solidified by using a copper wheel, rotating at 15 m/s, under an argon atmosphere. Chemical analysis of as-rapidly solidified ribbons indicated, that four alloy compositions lie in the β-(Ni, Cu)Al field, one alloy composition lie in the boundary of the β-(Ni, Cu)Al/(Ni, Cu)2Al3 fields, one alloy composition lies in the boundary of the β-(Ni, Cu)Al/β-(Ni, Cu)Al + (Ni, Cu)3Al fields and two alloy compositions lie in the β-(Ni, Cu)Al + (Ni, Cu)3Al field. Transmission electron microscopic observations carried out in as-rapidly solidified ribbons, revealed the presence of at least three main structures: i) β-(Ni, Cu)Al, ii) β-(Ni, Cu)Al + martensite (Ni, Cu)Al and iii) (Ni, Cu)3Al + martensite (Ni, Cu)Al. Microhardness Vickers and tensile test data indicated that alloys with a β-(Ni, Cu)Al + martensite (Ni, Cu)Al microstructure have improved room temperature ductility, reaching values of elongation up to 3.28 %.