This paper systematically investigated the effect of solution and artificial aging heat treatments on the microstructural evolution and mechanical properties of TiB/Ti-6Al-4V composites in situ fabricated by selective...This paper systematically investigated the effect of solution and artificial aging heat treatments on the microstructural evolution and mechanical properties of TiB/Ti-6Al-4V composites in situ fabricated by selective laser melting.The results showed that the fully martensite microstructure with TiB clusters of the as-built samples was transformed into lamellarα+βmicrostructure with TiB strips after solution heat treatment.With increasing the temperature,theαlaths and TiB particles coarsened and theβvolume fraction increased.After aging heat treatment,βvolume fraction decreased and TiB had no obvious changes.A superior combination of the yield strength of(1146.8±28.2)MPa and even higher plasticity and ultimate compressive strength((1680.1±18.3)MPa)than the as-built ones was obtained by solution heat treatment at 1000℃+water quenching and aging at 600℃for 6 hþair cooling.展开更多
A novel α+β titanium alloy with multi-alloying addition was designed based on the cluster formula 12[Al-Ti_(12)](AlTi_(2))+5[Al-Ti_(14)](AlV_(1.2)Mo_(0.6)Nb_(0.2))which was derived from Ti-6Al-4V.The nominal composi...A novel α+β titanium alloy with multi-alloying addition was designed based on the cluster formula 12[Al-Ti_(12)](AlTi_(2))+5[Al-Ti_(14)](AlV_(1.2)Mo_(0.6)Nb_(0.2))which was derived from Ti-6Al-4V.The nominal composition of this novel alloy was determined as Ti-6.83Al-2.28V-2.14Mo-0.69Nb-6.79Zr.In this study,the novel alloy and Ti-6Al-4V alloy samples were prepared by laser additive manufacturing.The microstructure,micro-hardness,room/high temperature tensile properties of the as-deposited samples were investigated.Compared to Ti-6Al-4V,the novel alloy has much higher room and high temperature(600℃)tensile strengths,which are 1,427.5 MPa and 642.2 MPa,respectively;however,it has a much lower elongation(3.2%)at room temperature because of the finer microstructure.To improve the elongation of the novel alloy,heat treatment was used.After solution at 960℃ or 970℃ for 1 h followed by air cooling and aging at 550℃ for 4 h followed by air cooling,a unique bi-modal microstructure which contains crab-like primaryαand residual β phase is obtained,improving the compression elongation by 80.9% compared to the as-deposited samples.The novel alloy can be used as a high-temperature and high-strength candidate for laser additive manufacturing.展开更多
In this study,TiC/CM247LC nickel-based composite was successfully prepared by selective laser melting,then was heat treated at a solid solution temperature of 1260℃and different aging temperature of 840℃,870℃,900℃...In this study,TiC/CM247LC nickel-based composite was successfully prepared by selective laser melting,then was heat treated at a solid solution temperature of 1260℃and different aging temperature of 840℃,870℃,900℃and 930℃respectively.Effects of aging temperatures on the microstructures and mechanical properties were systematically studied.The results show that the microstructures of all the heat treated samples are composed ofγmatrix,carbides andγ′phase.Theγgrains remain a columnar shape after treatments,but the size ofγ′phase grows up gradually with the increasing aging temperature.The composite treated at an aging temperature of 870℃exhibits the best mechanical properties with the tensile strength of 1073 MPa,yield strength of 1004 MPa and elongation of 7.57%.The plastic deformation and strengthening mechanisms of heat treated composite were systematically investigated.展开更多
Local annealing of amorphous NiTi thin films was performed by using an Nd：YAG 1064 nm wavelength pulsed laser beam. Raw samples produced by simultaneous sputter deposition from elemental Ni and Ti targets onto unheat...Local annealing of amorphous NiTi thin films was performed by using an Nd：YAG 1064 nm wavelength pulsed laser beam. Raw samples produced by simultaneous sputter deposition from elemental Ni and Ti targets onto unheated Si （100） and Silica （111） substrates were used for annealing. Delicate treatment with 15.92 W/mm^2 power density resulted in crystallization of small spots; while 16.52 and 17.51 W/mm^2 power densities caused ablation of the amorphous layer. Optical microscopy, scanning electron microscopy, X-ray diffraction and atomic force microscopy were performed to characterize the microstructure and surface morphology of the amorphous/crystallized spot patterns.展开更多
基金sponsored by the National Natural Science Foundation of China(Grant No.51775208,51922044)the Hubei Science Fund for Distinguished Young Scholars(No.0216110085)+1 种基金Wuhan Plan of Science and Technology(No.2018010401011281)the Academic Frontier Youth Team(2018QYTD04)at Huazhong University of Science and Technology(HUST).
文摘This paper systematically investigated the effect of solution and artificial aging heat treatments on the microstructural evolution and mechanical properties of TiB/Ti-6Al-4V composites in situ fabricated by selective laser melting.The results showed that the fully martensite microstructure with TiB clusters of the as-built samples was transformed into lamellarα+βmicrostructure with TiB strips after solution heat treatment.With increasing the temperature,theαlaths and TiB particles coarsened and theβvolume fraction increased.After aging heat treatment,βvolume fraction decreased and TiB had no obvious changes.A superior combination of the yield strength of(1146.8±28.2)MPa and even higher plasticity and ultimate compressive strength((1680.1±18.3)MPa)than the as-built ones was obtained by solution heat treatment at 1000℃+water quenching and aging at 600℃for 6 hþair cooling.
基金financially supported by the Shenyang Young and Middle-aged Scientific and Technological Innovation Talents Program(RC190490)the Liaoning Revitalization Talents Program(No.XLYC1808030)。
文摘A novel α+β titanium alloy with multi-alloying addition was designed based on the cluster formula 12[Al-Ti_(12)](AlTi_(2))+5[Al-Ti_(14)](AlV_(1.2)Mo_(0.6)Nb_(0.2))which was derived from Ti-6Al-4V.The nominal composition of this novel alloy was determined as Ti-6.83Al-2.28V-2.14Mo-0.69Nb-6.79Zr.In this study,the novel alloy and Ti-6Al-4V alloy samples were prepared by laser additive manufacturing.The microstructure,micro-hardness,room/high temperature tensile properties of the as-deposited samples were investigated.Compared to Ti-6Al-4V,the novel alloy has much higher room and high temperature(600℃)tensile strengths,which are 1,427.5 MPa and 642.2 MPa,respectively;however,it has a much lower elongation(3.2%)at room temperature because of the finer microstructure.To improve the elongation of the novel alloy,heat treatment was used.After solution at 960℃ or 970℃ for 1 h followed by air cooling and aging at 550℃ for 4 h followed by air cooling,a unique bi-modal microstructure which contains crab-like primaryαand residual β phase is obtained,improving the compression elongation by 80.9% compared to the as-deposited samples.The novel alloy can be used as a high-temperature and high-strength candidate for laser additive manufacturing.
基金he financial supports provided by the Shandong Provincial Natural Science Foundation General Program under Grant No.ZR2023ME062.
文摘In this study,TiC/CM247LC nickel-based composite was successfully prepared by selective laser melting,then was heat treated at a solid solution temperature of 1260℃and different aging temperature of 840℃,870℃,900℃and 930℃respectively.Effects of aging temperatures on the microstructures and mechanical properties were systematically studied.The results show that the microstructures of all the heat treated samples are composed ofγmatrix,carbides andγ′phase.Theγgrains remain a columnar shape after treatments,but the size ofγ′phase grows up gradually with the increasing aging temperature.The composite treated at an aging temperature of 870℃exhibits the best mechanical properties with the tensile strength of 1073 MPa,yield strength of 1004 MPa and elongation of 7.57%.The plastic deformation and strengthening mechanisms of heat treated composite were systematically investigated.
文摘Local annealing of amorphous NiTi thin films was performed by using an Nd：YAG 1064 nm wavelength pulsed laser beam. Raw samples produced by simultaneous sputter deposition from elemental Ni and Ti targets onto unheated Si （100） and Silica （111） substrates were used for annealing. Delicate treatment with 15.92 W/mm^2 power density resulted in crystallization of small spots; while 16.52 and 17.51 W/mm^2 power densities caused ablation of the amorphous layer. Optical microscopy, scanning electron microscopy, X-ray diffraction and atomic force microscopy were performed to characterize the microstructure and surface morphology of the amorphous/crystallized spot patterns.
