Thermal Explosion Preparation Sme Analysis Of Niti Shape Memory Alloy And Remelting Niti Alloy

porous and dense NiTi shape memory alloy have been prepared by self-propagating high-temperature synthesis (SHS) from Ni and Ti powder. The effect of the two crucial processing parameters, namely the heating mode and the green density, on combustion processing and microstructure of the products, were investigated. At the same time aimed at the problem of the production utilization rate is lower (not reach 20%) in traditional mode of production. Microstructure of remelted NiTi shape memory alloys were explored, at last making a failure analysis on shape memory effect of remelted shape memory alloys.Experiment result shows :Single phase NiTi shape memory alloys was successfully prepared using the thermal explosion mode of SHS combination. Heating mode and green density have great influence on the relative density of production; being with the increase of green density, the relative density of production keep the tend of fall; at heating rate above 20°C/min dense and single phase NiTi was prepared, it'relative density can reach 85%; at heating rate below 20°C/min porous yet single NiTi was prepared, it'porosity can reach 40%; the multiple phase of production were NiTi, Ti₂Ni and Ni₃Ti.By electric arc furnace and high-frequency induction furnace, casting NiTi alloy can be obtained from NiTi scrap stock, the shape memory effect of casting NiTi alloy was difference along with adopt difference crucible. There were gathering and grow up of TiC in casting NiTi alloys remelted in graphite pot, Ti₂Ni nucleated and grown up on TiC, herringbone like TiC and Ti₂Ni was uneven distribution on NiTi matrix and generated lattice defect. All of this destructive habit plane of martensite and generate resistance force during matrix transformation. As result shape memory effect fall or disappear.