Direct laser fabricated in situ TiC particulate reinforced Ni30Al20Fe intermetallic matrix composite

Abstract

NiAl intermetallics is considered to be a potential high temperature structural material based on a high melting point, low density, high thermal conductivity, excellent oxidation and hot-corrosion resistance at elevated temperatures [1–4], but its high temperature strength is insufficient for the majority of actual applications. The tensile ductility and fracture toughness at ambient temperatures are often also unsatisfactory [5, 6]. The solid solution strengthening, precipitation strengthening, directional solidification and single crystal technique have been explored to improve its high temperature strength. Although significant progress has been achieved, the ambient tensile ductility and fracture toughness often deteriorate as a result. On the other hand, the ductility and toughness can also be improved by microalloying, macroalloying and plastic secondary phase additions, but this is at the expense of the strength [4–7]. In other words, it is very difficult to compromise its high temperature strength and ambient temperature ductility. This severely restricts its operating temperature and deteriorates its machinability. It is significant to explore novel fabricaturing techniques for NiAl intermetallic alloy to improve its comprehensive mechanical properties. Preparing intermetallic matrix composite is an effective method to produce engineering NiAl intermetallic alloy and to improve its high temperature strength and retain ambient temperature ductility simultaneously [8, 9]. Good ductility can be obtained through adequately alloying the intermetallic matrix while the strength is improved with the reinforcements. The casting, combustion synthesis, powder metallurgy and mechanical alloying are major methods for preparing NiAl intermetallic matrix composites. Nevertheless, in many cases, the mechanical bonding due to no interfacial reaction, or the brittle reactive products existing at the interface between matrix and reinforcement due to excessive interfacial reaction often result in weak interfacial bonding so that whole properties