The iron aluminide Fe 3 Al has been successfully processed by selective laser melting (SLM) and laser metal deposition (LMD). Process parameters have been determined by which defect free and dense (.99.5%) samples were produced. However, due to the low thermal conductivity of Fe 3 Al, preheating the substrate to 200°C was necessary to prevent cracking during cooling. Microstructural characterization by electron backscatter diffraction (EBSD) showed that in spite of the high cooling rates large elongated grains grew in the building direction, more distinctive for SLM than for LMD. These grains show a continuous change in the crystallographic orientation. Evaluation of the compressive flow stress showed that the anisotropic microstructure results in anisotropic mechanical properties, depending whether the samples are loaded in building direction or perpendicular to it. The alloy shows a very high strength up to 600°C and -concerning the coarse microstructure -becomes ductile already at low temperatures.

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Doping of Fe–Al–Nb alloys with boron results in precipitation of stable C14 Laves phase Nb(Fe,Al)2 instead of metastable Heusler phase Fe2AlNb as in case of the ternary system. The boron stimulated precipitation of the Laves phase leads to preferential precipitation of the Laves phase along grain boundaries and – with higher supersaturation of Nb in the Fe-Al matrix – to an even distribution of additional precipitates within the grains. Though these microstructures seem to be more favourable than in the boron-free alloys, which show an uneven distribution of rather large Laves phase precipitates, no marked strengthening effect by the Laves phase in the Fe–Al–Nb–B alloys is observed.

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Reactions during compaction of Mo/Mo silicide wires with Ni interlayers are qualitatively assessed in this work. It appeared that due to extreme high temperature strength of MoSi2 hot pressing even at 1800°C/60 min/30 MPa in vacuum had not been sufficient to compact the Mo/Mo silicide wires in the absence of any additional interfacial layer. Therefore Ni had been chemically coated on the surface of Mo/Mo silicide wires that were subsequently compacted by hot pressing. Structural analysis revealed the reaction between Ni and MoSi2 resulting in the formation of ternary (MoNiSi) compounds. These established an interfacial bonding with minimal porosity.