The tungsten fibers or powders reinforced Zr_(52)Cu_(32)Ni_(6)Al_(10),(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Nb_(2),and(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Be_(2)bulk metallic glass composites(BMGCs)were fabricated using the ...The tungsten fibers or powders reinforced Zr_(52)Cu_(32)Ni_(6)Al_(10),(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Nb_(2),and(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Be_(2)bulk metallic glass composites(BMGCs)were fabricated using the infiltration casting method.In this study,the wettability between the amorphous alloy melts and tungsten substrates was investigated using the sessile drop method,revealing excellent wettability at 1,010℃.Consequently,an infiltration temperature of 1,010°C was chosen for composite material fabrication.Structural characterization and mechanical property test of both composites were conducted through scanning electron microscopy(SEM),and X-ray diffraction(XRD),and universal mechanical testing.Both tungsten fiber or tungsten powder reinforced Zr_(52)Cu_(32)Ni_(6)Al_(10)and(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Be_(2)composites exhibit the formation of W-Zr phase.In contrast,the tungsten fiber or tungsten powder reinforced(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Nb_(2)composites does not show the formation of W-Zr phase.X-ray diffraction patterns confirm the presence of W reinforcement phases in both composites.The successful fabrication of both composites is evidenced by their remarkable mechanical properties under room temperature compression.The yield strength of all the three tungsten fiber-reinforced composite sample exceeds 2,400 MPa,with the plastic strain exceeding 3.9%,while the yield strength of all the three tungsten powder-reinforced composite sample surpasses 2,700 MPa,with the plastic strain exceeding 30%.Fracture analysis reveals longitudinal splitting in the tungsten fiber-reinforced composites,contrasting with brittle fracture in the tungsten powder-reinforced composites.The denser the shear bands on the amorphous matrix of the two types of composite materials,the better their mechanical properties.展开更多
In this investigation,a new silicone rubber-based MRE material was prepared to be used as a forming medium in manufacturing thin-walled complexshaped Ni-based tubes through the bulging process.Thus,it is significant t...In this investigation,a new silicone rubber-based MRE material was prepared to be used as a forming medium in manufacturing thin-walled complexshaped Ni-based tubes through the bulging process.Thus,it is significant to investigate the effect of magnetic field intensity,magnetic field loading time,and angle on the mechanical properties of the prepared MRE material during the curing process.The obtained results showed that increasing the magnetic field intensity during the curing process can improve the orientation of the chain structure in the elastomer matrix effectively.However,its mechanical properties are the best under the corresponding magnetic field intensity of 321 mT.Besides,by extending the magnetic field loading time in the curing process,the orientation of the chain structure was optimized,at the same time,the mechanical properties were also improved,and the best loading time is about 20–25 min.By changing the loading angle of the magnetic field during the curing process,the mechanical properties of the MRE were improved.When the loading angle of the magnetic field is 90°,the elastomer showed the best compression mechanical properties and excellent compression reversibility.Besides,for the anisotropic MRE material,the performance with magnetic compression is always better than that without magnetic compression.展开更多
Metamaterials are defined as artificially designed micro-architectures with unusual physical properties,including optical,electromagnetic,mechanical,and thermal characteristics.This study investigates the compressive ...Metamaterials are defined as artificially designed micro-architectures with unusual physical properties,including optical,electromagnetic,mechanical,and thermal characteristics.This study investigates the compressive mechanical and heat transfer properties of AlSi10Mg gradient metamaterials fabricated by Laser Powder Bed Fusion(LPBF).The morphology of the AlSi10Mg metamaterials was examined using an ultrahigh-resolution microscope.Quasi-static uniaxial compression tests were conducted at room temperature,with deformation behavior captured through camera recordings.The findings indicate that the proposed gradient metamaterial exhibits superior compressive strength properties and energy absorption capacity.The Gradient-SplitP structure demonstrated better compressive performance compared to other strut-based structures,including Gradient-Gyroid and Gradient-Lidinoid structures.With an apparent density of 0.796,the Gradient-SplitP structure exhibited an outstanding energy absorption capacity,reaching an impressive 23.57 MJ/m^(3).In addition,heat conductivity tests were performed to assess the thermal resistance of these structures with different cell configurations.The gradient metamaterials exhibited higher thermal resistance and lower thermal conductivity.Consequently,the designed gradient metamaterials can be considered valuable in various applications,such as thermal management,load-bearing,and energy absorption components.展开更多
To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elas...To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.展开更多
The cyclic extrusion compression （CEC） was applied to severely deform the as-extruded GW102K （Mg- 10.0Gd-2.0Y-0.5Zr, wt%） alloy at 350, 400, and 450 ℃, respectively. The microstructure, texture, and grain boundar...The cyclic extrusion compression （CEC） was applied to severely deform the as-extruded GW102K （Mg- 10.0Gd-2.0Y-0.5Zr, wt%） alloy at 350, 400, and 450 ℃, respectively. The microstructure, texture, and grain boundary character distribution of the CECed alloy were investigated in the present work. The mechan- ical properties were measured by uniaxial tension at room temperature. The crack initiation on the longitudinal section near the tensile fracture-surface was investigated by high-resolution scanning elec- tron microscopy （SEM）. The result shows that the microstructure was dramatically refined by dynamic recrystallization （DRX）. The initial fiber texture was disintegrated and obviously weakened. The 8-passes/ 350 ℃ CECed alloy exhibited yield strength of 318 MPa with an elongation-to-fracture of 16.8%, increased by 41.3% and 162.5%, respectively. Moreover, the elongation-to-fracture of the 8-passes/450 ℃ CECed alloy significantly increased more than 3 times than that of the received alloy. The cracks were mainly initi- ated at twin boundaries and second phase/matrix interfaces during tensile deformation. The microstructure refinement was considered to result in the dramatically enhanced of the strength and ductility. In ad- dition, the texture randomization during CEC is beneficial for enhancing ductility. The standard positive Hall-Petch relationships have been obtained for the CECed GW102K alloy.展开更多
Strain-rate sensitivities of 55vol%-65vol% aluminum 2024-T6/TiB2 composites and the corresponding aluminum 2024-T6 matrix were investigated using split Hopkinson pressure bar method. The experimental results showed th...Strain-rate sensitivities of 55vol%-65vol% aluminum 2024-T6/TiB2 composites and the corresponding aluminum 2024-T6 matrix were investigated using split Hopkinson pressure bar method. The experimental results showed that 55vol%-65vol% aluminum 2024-T6/TiB2 composites exhibited significant strain-rate sensitivities, which were three times higher than the strain-rate sensitivity of the aluminum 2024-T6 matrix. The strain-rate sensitivity of the aluminum 2024-T6 matrix composites rose obviously with increasing reinforcement content（up to 60%）, which agreed with that from the previous researches. But it decreased as the ceramic reinforcement content reached 65%. After high strain rates compression, a large number of dislocations and micro-cracks were found inside the matrix and the Ti B2 particles, respectively. These micro-cracks can accelerate the brittle fracture of the composites. The aluminum 2024-T6/Ti B2 composites showed various fracture characteristics and shear instability was the predominant failure mechanism under dynamic loading.展开更多
基金support from the China Manned Space Engineering(YYMT1201-EXP08).
文摘The tungsten fibers or powders reinforced Zr_(52)Cu_(32)Ni_(6)Al_(10),(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Nb_(2),and(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Be_(2)bulk metallic glass composites(BMGCs)were fabricated using the infiltration casting method.In this study,the wettability between the amorphous alloy melts and tungsten substrates was investigated using the sessile drop method,revealing excellent wettability at 1,010℃.Consequently,an infiltration temperature of 1,010°C was chosen for composite material fabrication.Structural characterization and mechanical property test of both composites were conducted through scanning electron microscopy(SEM),and X-ray diffraction(XRD),and universal mechanical testing.Both tungsten fiber or tungsten powder reinforced Zr_(52)Cu_(32)Ni_(6)Al_(10)and(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Be_(2)composites exhibit the formation of W-Zr phase.In contrast,the tungsten fiber or tungsten powder reinforced(Zr_(52)Cu_(32)Ni_(6)Al_(10))_(98)Nb_(2)composites does not show the formation of W-Zr phase.X-ray diffraction patterns confirm the presence of W reinforcement phases in both composites.The successful fabrication of both composites is evidenced by their remarkable mechanical properties under room temperature compression.The yield strength of all the three tungsten fiber-reinforced composite sample exceeds 2,400 MPa,with the plastic strain exceeding 3.9%,while the yield strength of all the three tungsten powder-reinforced composite sample surpasses 2,700 MPa,with the plastic strain exceeding 30%.Fracture analysis reveals longitudinal splitting in the tungsten fiber-reinforced composites,contrasting with brittle fracture in the tungsten powder-reinforced composites.The denser the shear bands on the amorphous matrix of the two types of composite materials,the better their mechanical properties.
基金The funding for the investigation in this paper mainly comes from the following funds.Funded by the National Natural Science Foundation Key Project of China(Grant No.U1937206)the authors are Li,Xu,Guo,the specific grant numbers was RMB 100,000.Funded by the Jiangsu Province Key Research and Development Project(No.BE2019007-2)+2 种基金the authors are Abd,Cheng,the specific grant numbers was RMB 200,000.Funded by the Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(No.ASMA201903)the authors are Wu,Yang,Hu,the specific grant numbers was RMB 50,000.Funded by the Basic Scientific Research Operations(Approval No.NT2020015)the authors are Shen,Tao,Guo,the specific grant numbers was RMB 100,000.
文摘In this investigation,a new silicone rubber-based MRE material was prepared to be used as a forming medium in manufacturing thin-walled complexshaped Ni-based tubes through the bulging process.Thus,it is significant to investigate the effect of magnetic field intensity,magnetic field loading time,and angle on the mechanical properties of the prepared MRE material during the curing process.The obtained results showed that increasing the magnetic field intensity during the curing process can improve the orientation of the chain structure in the elastomer matrix effectively.However,its mechanical properties are the best under the corresponding magnetic field intensity of 321 mT.Besides,by extending the magnetic field loading time in the curing process,the orientation of the chain structure was optimized,at the same time,the mechanical properties were also improved,and the best loading time is about 20–25 min.By changing the loading angle of the magnetic field during the curing process,the mechanical properties of the MRE were improved.When the loading angle of the magnetic field is 90°,the elastomer showed the best compression mechanical properties and excellent compression reversibility.Besides,for the anisotropic MRE material,the performance with magnetic compression is always better than that without magnetic compression.
基金Supported by National Natural Science Foundation of China(Grant No.12272045)the BIT Research and Innovation Promoting Project(Grant No.2023YCXZ025).
文摘Metamaterials are defined as artificially designed micro-architectures with unusual physical properties,including optical,electromagnetic,mechanical,and thermal characteristics.This study investigates the compressive mechanical and heat transfer properties of AlSi10Mg gradient metamaterials fabricated by Laser Powder Bed Fusion(LPBF).The morphology of the AlSi10Mg metamaterials was examined using an ultrahigh-resolution microscope.Quasi-static uniaxial compression tests were conducted at room temperature,with deformation behavior captured through camera recordings.The findings indicate that the proposed gradient metamaterial exhibits superior compressive strength properties and energy absorption capacity.The Gradient-SplitP structure demonstrated better compressive performance compared to other strut-based structures,including Gradient-Gyroid and Gradient-Lidinoid structures.With an apparent density of 0.796,the Gradient-SplitP structure exhibited an outstanding energy absorption capacity,reaching an impressive 23.57 MJ/m^(3).In addition,heat conductivity tests were performed to assess the thermal resistance of these structures with different cell configurations.The gradient metamaterials exhibited higher thermal resistance and lower thermal conductivity.Consequently,the designed gradient metamaterials can be considered valuable in various applications,such as thermal management,load-bearing,and energy absorption components.
基金Project(LY13E080021) supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(2011A610072) supported by the Ningbo Municipal Natural Science Foundation,ChinaProject(XKL14D2063) supported by Subject Program of Ningbo University,China
文摘To investigate the mechanical properties of cement mortar in sodium sulfate and sodium chloride solutions, uniaxial compression test and ultrasonic test were performed. Test results show that the relative dynamic elastic modulus, the mass variation,and the compressive strength of cement mortar increase first, and then decrease with increasing erosion time in sodium sulfate and sodium chloride solutions. The relative dynamic elastic moduli and the compressive strengths of cement mortars with water/cement ratios of 0.55 and 0.65 in sodium sulfate solution are lower than those in sodium chloride solution with the same concentration at the420 th day of immersion. The compressive strength of cement mortar with water/cement ratio of 0.65 is more sensitive to strain rate than that with water/cement ratio of 0.55. In addition, the strain-rate sensitivity of compressive strength of cement mortar will increase under attacks of sodium sulfate or sodium chloride solution.
基金supported by the National Natural Science Foundation of China (No. 51204117)Program for the Top Young Academic Leaders of Higher Learning Institutions of Shanxithe Natural Science Foundation of Shanxi province (No. 2015021017)
文摘The cyclic extrusion compression （CEC） was applied to severely deform the as-extruded GW102K （Mg- 10.0Gd-2.0Y-0.5Zr, wt%） alloy at 350, 400, and 450 ℃, respectively. The microstructure, texture, and grain boundary character distribution of the CECed alloy were investigated in the present work. The mechan- ical properties were measured by uniaxial tension at room temperature. The crack initiation on the longitudinal section near the tensile fracture-surface was investigated by high-resolution scanning elec- tron microscopy （SEM）. The result shows that the microstructure was dramatically refined by dynamic recrystallization （DRX）. The initial fiber texture was disintegrated and obviously weakened. The 8-passes/ 350 ℃ CECed alloy exhibited yield strength of 318 MPa with an elongation-to-fracture of 16.8%, increased by 41.3% and 162.5%, respectively. Moreover, the elongation-to-fracture of the 8-passes/450 ℃ CECed alloy significantly increased more than 3 times than that of the received alloy. The cracks were mainly initi- ated at twin boundaries and second phase/matrix interfaces during tensile deformation. The microstructure refinement was considered to result in the dramatically enhanced of the strength and ductility. In ad- dition, the texture randomization during CEC is beneficial for enhancing ductility. The standard positive Hall-Petch relationships have been obtained for the CECed GW102K alloy.
基金Funded in part by the Fundamental Research Funds for the Central Universities,SCUT(2013ZZ014)the Natural Science Foundation of Guangdong Province(No.S2013010013269)+1 种基金the Doctoral Program Foundation of Institutions of Higher Education of China(No.20130172120027)the National Engineering Research Center Open Fund of SCUT(2011007B)
文摘Strain-rate sensitivities of 55vol%-65vol% aluminum 2024-T6/TiB2 composites and the corresponding aluminum 2024-T6 matrix were investigated using split Hopkinson pressure bar method. The experimental results showed that 55vol%-65vol% aluminum 2024-T6/TiB2 composites exhibited significant strain-rate sensitivities, which were three times higher than the strain-rate sensitivity of the aluminum 2024-T6 matrix. The strain-rate sensitivity of the aluminum 2024-T6 matrix composites rose obviously with increasing reinforcement content（up to 60%）, which agreed with that from the previous researches. But it decreased as the ceramic reinforcement content reached 65%. After high strain rates compression, a large number of dislocations and micro-cracks were found inside the matrix and the Ti B2 particles, respectively. These micro-cracks can accelerate the brittle fracture of the composites. The aluminum 2024-T6/Ti B2 composites showed various fracture characteristics and shear instability was the predominant failure mechanism under dynamic loading.
