Rapid solidification of intermetallic compounds

Abstract

This review surveys recent studies of rapid solidification at alloy compositions where the equilibrium phase is an intermetallic compound (or mixture of intermetallic compounds). Glass forming intermetallic compositions are considered and criteria for 'easy' glass formation are discussed. The limited data on synthesis of intermetallics from amorphous precursors are reviewed. This is a promising route to refine the microstructure of intermetallics with the potential for improved mechanical properties. It is an area that needs more study. The greatest effort has been devoted to studies of rapid solidification of the nickel-, iron-, or titanium-base aluminides. Rapid solidification of nickel base aluminides results in a refined microstructure (grain size and/or antiphase domain size) which can influence mechanical properties. The equilibrium crystal structure is maintained, however. Certain rapidly solidified Fe-AI-C base alloys can form a metastable fcc or L 1 2 structure (a point of continuing controversy) with good strength and ductility. The titanium base aluminides exhibit a marked tendency for formation of metastable structures on rapid quenching. The potential for improving the ductility of these compounds has made rapid solidification of Ti 3 AI and TiAI the subject of much recent activity.1MR/191

Metal Matrix Composites Reinforced With Intermetallic Ribbons

“…Table 2 which have beneficial effects on the mechanical properties of alloyed Ni 3A1 are boron (B) and hafnium (Hi). Boron is added in the amount of 0.75 at.% because its maximum ductilizing effect in the melt-spun Ni 3A1 occurs at this content (14). Hafnium improves creep properties as well as the yield strength at ambient temperatures (11) but it content must be kept below 1 at.% because above this value, ductility of boron-doped Ni 3A1 decreases drastically (11).…”

Electron beam surface melting of as cast and austempered ductile irons

“…The surface melted layer has usually a finer and more homogeneous structure than its original base material [1]. Extension of solid solubility and creation of metastable crystalline phases in the melted region are also possible [2]. This structure is often harder and more corrosion resistant than the untreated surface.…”

Effect of Milling Parameters on the TiB and TiB₂ Formation in Ti-50at%B and Ti-66at%B Powders

“…The intermetallic compounds can be interesting for high temperature structural applications due to their physical and chemical properties such as high melting point, and oxidation resistance [1][2][3][4][5][6]. In the Ti-B system, various works involving the preparation of the TiB and TiB 2 compounds by conventional arc-melting and powder metallurgy techniques were reported [7][8][9][10]. Recent studies indicated that the mechanical properties can be improved in as-cast Ti billets after severe plastic deformation by the equal channel angular extrusion (ECAE) [11,12].…”