Papers by Keyword: Ni₃Al Alloy

Abstract: Superposed-neutral-atom model and the finite-difference method (SNA-FD) are used to calculate the positron lifetime of different sizes and types of vacancy clusters in Ni3Al alloy. The calculated positron bulk lifetime in Ni3Al agrees well with the experimental results mentioned in literatures. The positron lifetimes of vacancy clusters with the same amount of vacancy but different components are also calculated. The results show that the positron lifetime is different when its components are different. The positron lifetimes of vacancy clusters with a single element but different sizes are also calculated. The result shows that the positron lifetime is almost a constant when its component is only Al vacancy, but the positron lifetime will increase at first and trend to be a constant when its component is only Ni vacancy.

Abstract: Research results focussed on the combined influence of iron and boron, in proportions of 0.5 and up to 10 wt.% respectively, in complex alloyed Ni3Al synthesised by Self Propagating High Temperature Synthesis (SHS) in the thermo-explosion mode at two ignition temperatures, 950 and 1150 oC, are presented. By XRD and Mössbauer spectroscopy it was established that for 950 oC ignition temperature, the evolved heat is not high enough for the added Fe to be fully incorporated into the synthesised Ni3Al phase, a temperature of 1150 oC being required. For this temperature, the density of the synthesised alloys, their capacity to be cold deformed by re-pressing, hardness and bending strength variations as a function of B and Fe contents, proved their cumulative effects of the ductility and mechanical properties of complex alloyed Ni3Al enhancing.