Iron Aluminium Alloys with Strengthening Carbides and Intermetallic Phases for High-Temperature Applications

Abstract

An overview of materials developments of iron aluminium alloys with strengthening precipitate phases is given. The discussion is focussed on recent studies on Fe-AI-based alloys with strengthening precipitates, such as x-phase Fe~ICx, MC-carbide and Laves phase. Alloys of the following alloy systems were investigated: Fe-AI-C, Fe-AI-Ta, Fe-AI-Ni, Fe-AI-Ti-Nb, and Fe-AI-M-C (M = Ti, V, Nb, Ta). The investigations were centred on microstructure, constitution, and mechanical properties of such Fe-AI-based alloys with AI contents ranging from 10 to 30 at. %. Mechanisms and problems are discussed and perspectives are outlined.

Concepts derived from phase diagram studies for the strengthening of Fe–Al-based alloys

“…In a second contribution by the same authors the strengthening in Fe-Al-M-C (MZTi, V, Nb, Ta) alloys by carbides and additional Laves phase has been studied [69]. Preliminary results of both studies have also been reported in [70].…”

Optimisation of precipitation for controlling recrystallisation of wrought Fe3Al based alloys

“…For Fe 3 Al based alloys it was demonstrated that precipitates such as carbides, borides and Laves phase are useful for strengthening [7][8][9]. Recent investigations revealed that the precipitates are effective for strengthening also at very high temperatures around 800 8C [10][11][12][13].…”

“…Serious problems are the limited ductility at low temperatures and the poor high-temperature strength and creep resistance. However, many investigations performed during the last two decades [3][4][5][6][7][8][9][10][11][12][13] have led to the improvement of each individual property. It is now the matter to combine these results and to optimise the fabrication processes for a novel Fe 3 Al based alloy with improved properties.…”

Alloys based on Fe3Al or FeAl with strengthening Mo3Al precipitates

“…Further strengthening may be achieved by ternary alloying which stabilises atomic ordering to higher temperatures, provides solid solution hardening and produces additional precipitate hardening [21,22]. A major project was performed to clarify the phase relations and equilibria in the ternary Fe -Al-Mo system and to screen the deformation characteristics of Fe -Al-base alloys with hardening intermetallic phases in this system.…”