| Effect of molybdenum on the combination of strength and ductility in age-hardenable Fe-8Ni-4Mn-4.5Cr-1Al-1Cu alloys has been studied by investigating age hardening, tensile properties, fractography and precipitation behaviors by scanning transmission electron microscope and energy dispersive X-ray spectroscopy. The molybdenum free alloy was surveyed severe embrittlement with aging due to preferred precipitation of large precipitates at the prior austenite grain boundary and martensite lath boundary, on the other hand, the alloy containing 2wt.% Mo showed a good combination of strength and ductility by preventing formation of large precipitates at these place, and then precipitating finely dispersive precipitates at the intragranular. But considerable drop in ductility was due to precipitation of large Laves Fe₂Mo phase at inter-and intragranular in alloys containing 4-6wt.% Mo. |
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