ABSTRACT
Electron beam additive manufacturing from dissimilar metal wires was used to intermix 5, 10 and 15 vol.% of Ti-Al-Mo-Z-V titanium alloy with CuAl9Mn2 bronze on a stainless steel substrate. The resulting alloys were subjected to investigations into their microstructural, phase and mechanical characteristics. It was shown that different microstructures were formed in an alloy containing 5 vol.% titanium alloy, as well as others containing 10 and 15 vol.%. The first was characterized by structural components such as solid solution, eutectic intermetallic compound TiCu2Al and coarse grains of γ1-Al4Cu9. It had enhanced strength and demonstrated steady oxidation wear in sliding tests. The other two alloys also contained large flower-like Ti(Cu,Al)2 dendrites that appeared due to the thermal decomposition of γ1-Al4Cu9. This structural transformation resulted in catastrophic embrittlement of the composite and changing of wear mechanism from oxidative to abrasive.
ABSTRACT
Novel composite CuA19Mn2/Udimet-500 alloy walls with different content of the Udimet 500 were built using electron-beam double-wire-feed additive manufacturing. Intermixing both metals within the melted pool resulted in dissolving nickel and forcing out the aluminum from bronze. The resulting phases were NiAl particles and grains, M23C6/NiAl core/shell particles and Cu-Ni-Al solid solution. Precipitation of these phases resulted in the increased hardness and tensile strength as well as reduced ductility of the composite alloys. Such a hardening resulted in improving the wear resistance as compared to that of source aluminum bronze.
