Study On The Fabrication And Properties Of Porous NiTi Based High Damping Materials

To develop high damping materials with excellent comprehensive properties to meet the urgent needs of vibration and noise reduction in many areas of society.In this paper,porous NiTi and porous NiTiCu shape memory alloys(SMAs)were prepared by using NaCl as space-holders via sintering dissolution process.In addition,a Mg/NiTiCu composite with high damping and low density was also prepared by filling Mg into the pores of porous NiTiCu SMA via pressureless infiltration technique.In this paper,SEM,XRD,DSC,DMA and universal material testing machine were used to characterize and test the macro and micro morphologies,phase composition,phase change behavior,damping and energy absorption properties of the materials.It was found that,after optimizing the process,the porous NiTi and porous NiTiCu SMAs with controllable pore size and porosity,as well as regular and uniformly distributed open pores could be successfully prepared.Deficiencies in the preparation of such materials was therefore resolved.The porous NiTi and NiTiCu SMAs prepared in the present study possess excellent damping and compression energy absorption properties.At the same time,due to the replacement of Ni by Cu,the latter has more stable martensitic transformation properties than the former.Co MPared with the porous NiTiCu SMA,the Mg/NiTiCu composites prepared by pressureless infiltration technique possess significantly improved compressive strength,compressive energy absorption and damping properties.This can be attributed to the composite effect of the mechanical properties and the superposition of multiple damping sources of Mg/NiTiCu composites.Therefore,the Mg/NiTiCu composite is a new kind of high damping material with the integration of function and structure.The successful preparation of this material can provide a new idea for the design and development of the new generation of high damping materials.