Preparation And Characterization Of Superelastic NiTi/Polyurethane Damping Composite Materials

Constrained damping composite material, as a novel high damping material, is able toeffectively reduce tha vibration and decrease the noise. The paper combines superealstic NiTialloy with polyurethane to form a as the contrained layer to combine with SuperelasticNiTi/polyurethane Damping Composite Material with a sandwich structure. The transformationbehavior and mechanical properties of NiTi as well as the damping properties of the compositematerial are systematically studied.In order to obtain a good superelasticity, the transformation behavior, mechanical propertiesand superelasticity are studied. It is shown that, after aging at600oC for30min, NiTi is in fullpartent phase exhibiting a excellent superelasticity. The tensile strength and rate are697MPa and32.4%, respectively. Furthermore, the tensile cycle and loading speed have obvious effect on thesuperelasticity. In the case of0.1%/min, the remaining strain is the smallest, while thesuperelasticity is the highest. The increased tensile cycles make the superelasticity more stable.Then, NiTi alloy with excellent superelasticity is combined with polyurethane by adhesivebonding and hot pressing methods to prepare single-damping layer and multiple-damping layerSuperelastic NiTi/polyurethane Damping Composite Material. The damping loss factor ofcomposite material fabricated by these two methods both increases with increasing the thicknessof damping layer and shift to higher temperature with the increase of vibration frequency. Themaximum damping loss factor is up to0.32, which occurs in the one fabricated by adhesivebonding method. For the multiple-damping layer composte material obtaiened by hot pressingmethod, the damping loss factor show increasing tendeny with increasing the amount of dampinglayers. The damping loss factor is0.24in four-damping layer composite material.The interlaminar bonding strength of hot pressed composite was remarkably improved bygrinding the surface of NiTi alloy. The increase of the thickness of damping layer results in thereduction of interlaminar bonding strength. For the damping composite material by adhesivebonding method,which after soaking in various media for30days, the effect of engine oil isminimum, the anhydrous ethanol is maximum, while the artificial sea water is medium. For thedamping composite material by hot pressing method, which after soaking in various media for30days, the effect of engine oil is minimum, the anhydrous ethanol is maximum, while the artificialsea water is medium. The bending properties of the damping composite material by adhesive bonding method isbetter than the bending propertise of the damping composite material by hot pressing method.When the thickness of damping layer is2mm, the bending properties is best. The bendingpropertise of the four-damping layer composite material is maximum.