| High-damping alloys have been used in aerospace,automobile and other fields due to its capacity to weaken vibration and noise.The Ti-36Nb-2Ta-3Zr-0.3O alloy(Gum Metal)simultaneously possesses high strength and high damping properties.In order to obtain alloy with better mechanical and damping properties,this project carried on element reduction design which based on the Gum Metal.The Ti-36Nb-xTa-y Zr-0.3O alloy was prepared through vacuum non-consumable arc melting furnace.The influence of the Ta,Zr elements and solution temperature on microstructures,damping and mechanical properties of the Ti-36Nb-x Ta-yZr-0.3O alloy had been investigated by X-ray diffraction,tensile testing machine and dynamic mechanical analyzer.The hot-rolled Ti-36Nb-2Ta-3Zr-0.3O alloy existed high strength which mainly stemmed from the solution strengthening of interstitial oxygen atoms.In addition,it also possessed good damping properties.Compared with the Ti-36Nb-2Ta-3Zr-0.3O alloy,the tensile strength and damping capacity of the hot-rolled Ti-36Nb-3Zr-0.3O alloy decreased.This phenomenon may relate to the strong interaction of the Zr and O atoms which leading to the proportion of oxygen atoms reduced,so that the interstitial solution strengthening and the relaxation strength both decreased.The tensile strength and damping capacity of the hot-rolled Ti-36Nb-2Ta-0.3O alloy were increased,comparing to the Ti-36Nb-2Ta-3Zr-0.3O alloy.This may due to the restriction effect of the Ta to O atoms was weakest.Compared with the three alloys mentioned above,the tensile strength of the hot-rolled Ti-36Nb-0.3O alloy increased slightly and the damping capacity increased obviously.This phenomenon was related to the alloy without Ta,Zr elements occurred recrystallization during hot-rolled process,which consisted of fine equiaxed grains,coupled with the proportion of oxygen atoms which could participate in the relaxation process increased.The fine grain strengthening and interstitial solution strengthening effect made the tensile strength of the hot-rolled Ti-36Nb-0.3O alloy increased.Since there was fine ? phase in the hot-rolled Ti-36Nb-3Ta-0.3O alloy,its damping capacity decreased slightly,while the second phase strengthening and interstitial solution strengthening effect made the tensile strength of this alloy increased.Therefore,this project further studied the influence of solution temperature on the microstructures,damping and mechanical properties of the Ti-36Nb-0.3O and Ti-36Nb-3Ta-0.3O alloys.The tensile strength of the solution-treated Ti-36Nb-0.3O alloy was higher than the hot-rolled alloy.With the increasing of solution temperature,the tensile strength of the Ti-36Nb-0.3O alloydecreased,while the damping capacity first increased and then decreased.The damping capacity of Ti-36Nb-0.3O alloy solution-treated at 1163 K was the highest.When the vibration frequency was 0.1Hz,the damping capacity and tensile strength of the Ti-36Nb-0.3O alloy solution-treated at 1163 K were 0.0464 and 865 MPa,respectively,which simultaneously possesses high damping and high strength.This phenomenon was related to the grain size of the alloy solution-treated at 1083 K significantly decreased compared to the hot-rolled Ti-36Nb-0.3O alloy,and there were many fine and dispersed ? phases.The grain size of the alloy solution-treated at 1123 K increased slightly while the volume fracture of the ? phase decreased obviously.When solution-treated at 1163 K and 1203 K,there was no ? phase in Ti-36Nb-0.3O alloy,and its grain size increased further.The tensile strength of the solution-treated Ti-36Nb-3Ta-0.3O alloy was higher than the hot-rolled alloy.With the increasing of solution temperature,the tensile strength of Ti-36Nb-3Ta-0.3O alloy decreased while the damping capacity increased.The damping capacity of Ti-36Nb-3Ta-0.3O alloy solution-treated at 1203 K was highest.When the vibration frequency was 0.1 Hz,the damping capacity and tensile strength of this alloy were 0.0458 and 842 MPa,respectively,which had high damping and high strength simultaneously.This phenomenon was related to the grain size of the Ti-36Nb-3Ta-0.3O alloy solution-treated at 1083 K was nonuniform and there was many dispersed ?phase.The grain size of the alloy solution-treated at 1123 K decreased slightly and became uniform while the volume fracture of the ? phase decreased obviously.The grain size of the alloy solution-treated at 1163 K increased slightly while the volume fracture of the ? phase decreased significantly.When solution-treated at 1203 K,there was no ? phase in Ti-36Nb-3Ta-0.3O alloy,and their grain size increased further. |
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