This work investigated the effect of process parameters on densification,microstructure,and mechanical properties of a nickel-aluminum-bronze(NAB)alloy fabricated by laser powder bed fusion(LPBF)additive manufacturing...This work investigated the effect of process parameters on densification,microstructure,and mechanical properties of a nickel-aluminum-bronze(NAB)alloy fabricated by laser powder bed fusion(LPBF)additive manufacturing.The LPBF-printed NAB alloy samples with relative densities of over 98.5%were obtained under the volumetric energy density range of 200−250 J/mm^(3).The microstructure of the NAB alloy printed in both horizontal and vertical planes primarily consisted ofβ'martensitic phase and bandedαphase.In particular,a coarser-columnar grain structure and stronger crystallographic texture were achieved in the vertical plane,where the maximum texture intensity was 30.56 times greater than that of random textures at the(100)plane.Increasing the volumetric energy density resulted in a decrease in the columnar grain size,while increasing the amount ofαphase.Notably,β_(1)'martensitic structures with nanotwins and nanoscaleκ-phase precipitates were identified in the microstructure of LPBF-printed NAB samples with a volumetric energy density of 250 J/mm^(3).Furthermore,under optimal process parameters with a laser power of 350 W and scanning speed of 800 mm/s,significant improvements were observed in the microhardness(HV 386)and ultimate tensile strength(671 MPa),which was attributed to an increase in refined acicular martensite.展开更多
The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness...The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.展开更多
Generally,bulk metallic glasses(BMGs)exhibit a very limited plastic deformation under a compression load at room temperature,often less than 2% before fracturing.In this letter,through an appropriate choice of BMGs...Generally,bulk metallic glasses(BMGs)exhibit a very limited plastic deformation under a compression load at room temperature,often less than 2% before fracturing.In this letter,through an appropriate choice of BMGs' composition,an amorphous rod of Zr64.80Cu14.85Ni10.35Al10 with a diameter of 2 mm was prepared by using copper mold suction casting.X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability,and the uniaxial compression test was adopted to study its plastic deformation behavior at room temperature simultaneously.The results showed that the glass transition temperature and onset temperature of the exothermic reaction of the amorphous rod were 646 and 750 K,respectively,and its micro-hardness was 594.7 Hv.During com-pression,when the engineering strain and engineering stress arrived at 9.05% and 1732 MPa,respec-tively,i.e.,the true strain and true stress reached 9.42% and 1560 MPa,respectively,the amorphous rod started to yield.After yielding,with the increase of load,the strain increased and the glass rod ulti-mately were compressed into flake-like form.Although the maximum engineering strain was larger than 70%,i.e.,the maximum true strain exceeded by 120%,the amorphous specimen was not fractured,indicating that it has super-plasticity at room temperature.Through the appropriate choice of compo-sition and optimization of the technological process,flexible BMG with super-plasticity at room tem-perature could be produced.展开更多
基金Project(2022A1515010304)supported by the Guangdong Basic and Applied Basic Research Foundation,ChinaProject(52305358)supported by the National Natural Science Foundation of China+2 种基金Project(2023QNRC001)supported by the Young Elite Scientists Sponsorship Program by China Association for Science and TechnologyProject(QT-2023-001)supported by the Young Talent Support Project of Guangzhou,ChinaProject(2023ZYGXZR061)supported by the Fundamental Research Funds for the Central Universities,China。
文摘This work investigated the effect of process parameters on densification,microstructure,and mechanical properties of a nickel-aluminum-bronze(NAB)alloy fabricated by laser powder bed fusion(LPBF)additive manufacturing.The LPBF-printed NAB alloy samples with relative densities of over 98.5%were obtained under the volumetric energy density range of 200−250 J/mm^(3).The microstructure of the NAB alloy printed in both horizontal and vertical planes primarily consisted ofβ'martensitic phase and bandedαphase.In particular,a coarser-columnar grain structure and stronger crystallographic texture were achieved in the vertical plane,where the maximum texture intensity was 30.56 times greater than that of random textures at the(100)plane.Increasing the volumetric energy density resulted in a decrease in the columnar grain size,while increasing the amount ofαphase.Notably,β_(1)'martensitic structures with nanotwins and nanoscaleκ-phase precipitates were identified in the microstructure of LPBF-printed NAB samples with a volumetric energy density of 250 J/mm^(3).Furthermore,under optimal process parameters with a laser power of 350 W and scanning speed of 800 mm/s,significant improvements were observed in the microhardness(HV 386)and ultimate tensile strength(671 MPa),which was attributed to an increase in refined acicular martensite.
文摘The effect of diamond-like carbon(DLC)coating(fabricated by cathodic arc deposition)on mechanical properties,tribological behavior and corrosion performance of the Ni−Al−bronze(NAB)alloy was investigated.Nano-hardness and pin-on-plate test showed that DLC coating had a greater hardness compared with NAB alloy.Besides,the decrease in friction coefficient from 0.2 for NAB substrate to 0.13 for the DLC-coated sample was observed.Potentiodynamic polarization and EIS results showed that the corrosion current density decreased from 2.5μA/cm2 for bare NAB alloy to 0.14μA/cm2 for DLC-coated sample in 3.5 wt.%NaCl solution.Moreover,the charge transfer resistance at the substrate−electrolyte interface increased from 3.3 kΩ·cm2 for NAB alloy to 120.8 kΩ·cm2 for DLC-coated alloy,which indicated an increase in corrosion resistance due to the DLC coating.
基金the National Natural Sciences Foundation of China(Grant Nos.50771077 and 50371020)the Natural Science Foundation of Guangdong Prov-ince,China(Grant No.06021473)
文摘Generally,bulk metallic glasses(BMGs)exhibit a very limited plastic deformation under a compression load at room temperature,often less than 2% before fracturing.In this letter,through an appropriate choice of BMGs' composition,an amorphous rod of Zr64.80Cu14.85Ni10.35Al10 with a diameter of 2 mm was prepared by using copper mold suction casting.X-ray diffraction and differential scanning calorimetry were utilized to determine its structure and thermal stability,and the uniaxial compression test was adopted to study its plastic deformation behavior at room temperature simultaneously.The results showed that the glass transition temperature and onset temperature of the exothermic reaction of the amorphous rod were 646 and 750 K,respectively,and its micro-hardness was 594.7 Hv.During com-pression,when the engineering strain and engineering stress arrived at 9.05% and 1732 MPa,respec-tively,i.e.,the true strain and true stress reached 9.42% and 1560 MPa,respectively,the amorphous rod started to yield.After yielding,with the increase of load,the strain increased and the glass rod ulti-mately were compressed into flake-like form.Although the maximum engineering strain was larger than 70%,i.e.,the maximum true strain exceeded by 120%,the amorphous specimen was not fractured,indicating that it has super-plasticity at room temperature.Through the appropriate choice of compo-sition and optimization of the technological process,flexible BMG with super-plasticity at room tem-perature could be produced.
