The tungsten particles reinforced Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit 1 alloy) bulk metallic glass composites (BMGCs) were prepared by the melt infiltrating casting method with the infiltrating time of 1, 5 and 10 min, ...The tungsten particles reinforced Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit 1 alloy) bulk metallic glass composites (BMGCs) were prepared by the melt infiltrating casting method with the infiltrating time of 1, 5 and 10 min, respectively. The changes of interfacial reaction and compression properties of the bulk metallic glass composites with different infiltrating times were studied. Results show that with the increase of infiltrating time, tiny nanocrystals are generated at the interfacial boundary of tungsten particles and the amorphous matrix, and the size of tiny crystals increases with the infiltrating time. When the infiltrating time is 10 min, polygonal crystals with a larger size are also generated within the amorphous matrix. The compressive strength of the composites also increases with the infiltrating time. When the infiltrating time is 10 min, the compressive strength of the composite reaches 2,030 MPa and the compression strain is 44%. The fracture morphology of the composite materials is in a vein-like pattern and the melting phenomenon is found on the fracture surface. In addition, the density of the shear bands during the compressive tests of the composite materials increases with the infiltrating time.展开更多
In the present study, creep properties of as-cast Mg-5Al-5Ca-2Sn(AXT552) alloy were investigated by means of a GWT304 creep testing machine at temperatures of 175 °C and 200 °C in the stress range of 35-90 M...In the present study, creep properties of as-cast Mg-5Al-5Ca-2Sn(AXT552) alloy were investigated by means of a GWT304 creep testing machine at temperatures of 175 °C and 200 °C in the stress range of 35-90 MPa. Results show that creep rates increase with applied stress at an identical temperature. Creep strain at 100 hours is 0.0518% and 0.083% at creep conditions of 175°C/75 MPa and 200°C/60 MPa, respectively, which is comparable to MRI230 D and much lower than most of AX series alloys. By the observation and analysis for samples before and after creep tests using a Shimadzu XRD-7000 type X-ray diffractometer(XRD) and a Hitachi S-3400 N type scanning electron microscope(SEM), it was found that Al_2Ca(C15) phase precipitated out of C36 phase or matrix. The cavity formation and connection at the interface of soft matrix and hard intermetallics caused the propagation of cracking along the eutectic phase during creep process and dislocation accommodated grain/phase boundary sliding is expected to be the dominant creep mechanism.展开更多
Dealloyed ribbons with a layer of networked nanoporous structure of different pore sizes were fabricated by dealloying the as-spun Mg_(65)Cu_(25-x)Ag_(x)Y_(10)(x=0,5,10,at.%)ribbons in dilute H_(2)SO_(4) solution in o...Dealloyed ribbons with a layer of networked nanoporous structure of different pore sizes were fabricated by dealloying the as-spun Mg_(65)Cu_(25-x)Ag_(x)Y_(10)(x=0,5,10,at.%)ribbons in dilute H_(2)SO_(4) solution in order to enhance the degradation efficiency of pesticide wastewater.Compared to the as-spun ribbons,it is found that the dealloyed ribbons with the networked nanoporous structure exhibit higher degradation efficiency due to their large specific surface areas and enough active sites for the degradation process.Both the average pore sizes of the nanoporous structure and the degradation efficiency of the pesticide wastewater increase with the increase of Ag addition in the dealloyed ribbons.The maximum degradation efficiency up to 95.8%is obtained for the Mg_(65)Cu_(15)Ag_(10)Y_(10)dealloyed ribbon under the optimal conditions of pH being 3,the initial cis-cypermethrin concentration being 500 mg/L,and the dosage of dealloyed ribbon being 1.33 g/L.展开更多
The thin ribbons and the bulk cylindrical rods with diameters of 2 mm and 10 mm of the Vit1 metallic glass(MG)were prepared by the single roller melt spinning method and the copper mold injection casting method,respec...The thin ribbons and the bulk cylindrical rods with diameters of 2 mm and 10 mm of the Vit1 metallic glass(MG)were prepared by the single roller melt spinning method and the copper mold injection casting method,respectively.The cooling rates of the samples during melt solidification were evaluated.The glass transition behaviors of three groups of MG samples with different solidification cooling rates were studied by differential scanning calorimetry(DSC)at different heating rates.The effects of melt cooling rate on the glass transition kinetic parameters such as apparent activation energy(E)and fragility parameter(m)of the Vit1 MG were studied using the Kissinger and the Vogel-Fulcher-Tammann(VFT)equations.Additionally,the structural relaxation enthalpy(ΔHrel)of three groups of MG samples was quantitatively analyzed by DSC through multi-step temperature rise and fall measurements.Results show that the melt cooling rate(R)has a significant effect on the glass transition kinetics and the structural relaxation of the Vit1 MG.As R decreases in the order of magnitude,the glass transition temperature(Tg),E,m,andΔHrel of the Vit1 MG gradually decreases.Furthermore,in the range of the experimental cooling rates,E,m,andΔHrel all have an approximately linear relationship with lgR.展开更多
Fe-based bulk metallic glasses(BMGs)with high boron content have potential application as a coating material used in the framework for storing spent nuclear fuels to support their safe long-term disposal.The high glas...Fe-based bulk metallic glasses(BMGs)with high boron content have potential application as a coating material used in the framework for storing spent nuclear fuels to support their safe long-term disposal.The high glass forming ability(GFA)and large supercooled liquid region are therefore required for such Fe-based BMGs in either the glassy powder fabrication or the subsequent coating spraying.In order to meet these requirements,the influence of Nb content on the GFA of Fe_(57)Cr_(10)Zr_(8)B_(18)Mo_(7-x)Nb_(x)(x=1-5,at.%)alloys was investigated,as Nb has positive roles in GFA and thermal stability of BMGs.The results indicate that a fully amorphous phase in the as-cast samples with 3 mm in diameter is obtained for both the Fe_(57)Cr_(10)Zr_(8)B_(18)Mo_(5)Nb_(2) and Fe_(57)Cr_(10)Zr_(8)B_(18)Mo_(4)Nb_(3) alloys.The corresponding supercooled liquid regions of the two BMGs are 78 K and 71 K,respectively.The mechanism for improving their GFA was analyzed based on the principle of metal solidification,the parameters for glass formation and thermal properties of the alloys.The compression strength and Vicker’s hardness of the two BMGs are 1,950 MPa and 1,310 HV,2,062 MPa and 1,180 HV,respectively.The developed BMGs with high B content,good GFA,and very high hardness can be used as coating materials to the framework for spent nuclear fuels.展开更多
In this study, in order to investigate the influence of Cr element on the impact fracture process of ductile Ni-resistant alloyed iron at low temperature, different contents of Cr element were added to ductile Ni-resi...In this study, in order to investigate the influence of Cr element on the impact fracture process of ductile Ni-resistant alloyed iron at low temperature, different contents of Cr element were added to ductile Ni-resistant(DNR) austenitic alloyed iron. The experimental results show that Cr addition can increase the hardness of the DNR alloyed iron, but it has an destructive effect on low-temperature impact properties. Through the analysis of the dynamic load and absorbed energy of samples with different Cr contents in the impact fracture process, and the comparison of the impact fracture process at room and low temperatures, it reveals that Cr addition into the DNR alloyed iron can facilitate the formation of the carbide mixture in Mn23C6 and Cr23C6 with homogeneous and discontinuous distribution. Meanwhile, Cr addition also can improve the the maximum dynamic load and crack initiation energy at low temperature, but has no obvious effect on the yield behavior of the DNR alloyed iron in the impact fracture process. Compared with the impact crack propagation process at room temperature, the metastable propagation energy at low temperature declines significantly with an increase in Cr content. This is because the micro-cracks that caused by the carbides weaken the matrix, resulting in the decline of impact crack propagation resistance. The fracture analysis results also show that the impact fracture mechanism gradually transforms from ductile to brittle with an increase in Cr content at low temperature. It explains that too much Cr addition can lead to brittle fracture even though the austenitic matrix has a good toughness at low temperature.展开更多
Arc melting was utilized in this study to produce Zr_(55)Cu_(30)Ni_5Al_(10) alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidificatio...Arc melting was utilized in this study to produce Zr_(55)Cu_(30)Ni_5Al_(10) alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidification structure and glass-forming ability of Zr_(55)Cu_(30)Ni_5Al_(10) alloy were determined by examining microstructures in different parts of the cast ingots. The results showed that different degrees of crystallization structures were obtained in the ascast button ingots after arc melting in high-purity Ar, and the cross-sectional solidification morphology of arcmelted ingots was found to consist of crystals with varying from the bottom up. By contrast, there were completely amorphous structures in the middle and upper areas of the as-cast button ingots fabricated by adding 10% H_2 to the high-purity Ar atmosphere. A clear solidification interface was found between the crystal and glass in the ascast button ingots, which indicates that hydrogen addition can enhance the Zr_(55)Cu_(30)Ni_5Al_(10) alloy's glass-forming ability. The precise mechanism responsible for this was also investigated.展开更多
目的探讨麻醉管理优化方案结合单孔腹腔镜手术对患者快速康复的影响。方法将68例妇科良性肿瘤患者随机分成对照组和ERAS组,对照组患者采用三孔腹腔镜手术结合常规麻醉管理方案,ERAS组患者采用单孔腹腔镜手术结合优化后的麻醉管理方案。...目的探讨麻醉管理优化方案结合单孔腹腔镜手术对患者快速康复的影响。方法将68例妇科良性肿瘤患者随机分成对照组和ERAS组,对照组患者采用三孔腹腔镜手术结合常规麻醉管理方案,ERAS组患者采用单孔腹腔镜手术结合优化后的麻醉管理方案。比较2组手术时间、拔管时间、复苏室停留时间、达出院标准时间、术后肛门排气时间、术后住院时间及术后30 min、2 h、12 h、24 h VAS评分。比较2组术后恶心呕吐及切口出血、感染等情况。结果ERAS组手术时间、拔管时间、达出院标准时间、术后肛门排气时间、术后住院时间短于对照组,差异均有统计学意义(P<0.05)。2组复苏室停留时间、恶心呕吐发生率比较,差异无统计学意义(P>0.05)。2组患者术后均无切口出血、感染等情况发生。与对照组比较,ERAS组术后30 min VAS评分更高,其余时间点VAS评分更低(P<0.05)。结论优化后的麻醉管理策略结合单孔腔镜手术能减轻患者痛苦,缩短住院时间,促进患者快速康复。展开更多
基金This work was supported by the Liaoning Joint Fund of NSFC(No.U1908219).
文摘The tungsten particles reinforced Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vit 1 alloy) bulk metallic glass composites (BMGCs) were prepared by the melt infiltrating casting method with the infiltrating time of 1, 5 and 10 min, respectively. The changes of interfacial reaction and compression properties of the bulk metallic glass composites with different infiltrating times were studied. Results show that with the increase of infiltrating time, tiny nanocrystals are generated at the interfacial boundary of tungsten particles and the amorphous matrix, and the size of tiny crystals increases with the infiltrating time. When the infiltrating time is 10 min, polygonal crystals with a larger size are also generated within the amorphous matrix. The compressive strength of the composites also increases with the infiltrating time. When the infiltrating time is 10 min, the compressive strength of the composite reaches 2,030 MPa and the compression strain is 44%. The fracture morphology of the composite materials is in a vein-like pattern and the melting phenomenon is found on the fracture surface. In addition, the density of the shear bands during the compressive tests of the composite materials increases with the infiltrating time.
文摘In the present study, creep properties of as-cast Mg-5Al-5Ca-2Sn(AXT552) alloy were investigated by means of a GWT304 creep testing machine at temperatures of 175 °C and 200 °C in the stress range of 35-90 MPa. Results show that creep rates increase with applied stress at an identical temperature. Creep strain at 100 hours is 0.0518% and 0.083% at creep conditions of 175°C/75 MPa and 200°C/60 MPa, respectively, which is comparable to MRI230 D and much lower than most of AX series alloys. By the observation and analysis for samples before and after creep tests using a Shimadzu XRD-7000 type X-ray diffractometer(XRD) and a Hitachi S-3400 N type scanning electron microscope(SEM), it was found that Al_2Ca(C15) phase precipitated out of C36 phase or matrix. The cavity formation and connection at the interface of soft matrix and hard intermetallics caused the propagation of cracking along the eutectic phase during creep process and dislocation accommodated grain/phase boundary sliding is expected to be the dominant creep mechanism.
基金the financial supports from State Key Laboratory of Light Alloy Casting Technology for High-end Equipmentthe Natural Science Foundation of Liaoning Province,China(No.2020-KF-14-03)the National Natural Science Foundation of China(No.51775353)。
文摘Dealloyed ribbons with a layer of networked nanoporous structure of different pore sizes were fabricated by dealloying the as-spun Mg_(65)Cu_(25-x)Ag_(x)Y_(10)(x=0,5,10,at.%)ribbons in dilute H_(2)SO_(4) solution in order to enhance the degradation efficiency of pesticide wastewater.Compared to the as-spun ribbons,it is found that the dealloyed ribbons with the networked nanoporous structure exhibit higher degradation efficiency due to their large specific surface areas and enough active sites for the degradation process.Both the average pore sizes of the nanoporous structure and the degradation efficiency of the pesticide wastewater increase with the increase of Ag addition in the dealloyed ribbons.The maximum degradation efficiency up to 95.8%is obtained for the Mg_(65)Cu_(15)Ag_(10)Y_(10)dealloyed ribbon under the optimal conditions of pH being 3,the initial cis-cypermethrin concentration being 500 mg/L,and the dosage of dealloyed ribbon being 1.33 g/L.
基金supported by the National Key Research and Development Program of China(No.2019YFB2006501)。
文摘The thin ribbons and the bulk cylindrical rods with diameters of 2 mm and 10 mm of the Vit1 metallic glass(MG)were prepared by the single roller melt spinning method and the copper mold injection casting method,respectively.The cooling rates of the samples during melt solidification were evaluated.The glass transition behaviors of three groups of MG samples with different solidification cooling rates were studied by differential scanning calorimetry(DSC)at different heating rates.The effects of melt cooling rate on the glass transition kinetic parameters such as apparent activation energy(E)and fragility parameter(m)of the Vit1 MG were studied using the Kissinger and the Vogel-Fulcher-Tammann(VFT)equations.Additionally,the structural relaxation enthalpy(ΔHrel)of three groups of MG samples was quantitatively analyzed by DSC through multi-step temperature rise and fall measurements.Results show that the melt cooling rate(R)has a significant effect on the glass transition kinetics and the structural relaxation of the Vit1 MG.As R decreases in the order of magnitude,the glass transition temperature(Tg),E,m,andΔHrel of the Vit1 MG gradually decreases.Furthermore,in the range of the experimental cooling rates,E,m,andΔHrel all have an approximately linear relationship with lgR.
基金the Liaoning Joint Fund of NSFC(No.U1908219)Natural Science Foundation of Liaoning(No.2020-KF-14-03)National Key Research and Development Program of China(No.2019YFB2006501)。
文摘Fe-based bulk metallic glasses(BMGs)with high boron content have potential application as a coating material used in the framework for storing spent nuclear fuels to support their safe long-term disposal.The high glass forming ability(GFA)and large supercooled liquid region are therefore required for such Fe-based BMGs in either the glassy powder fabrication or the subsequent coating spraying.In order to meet these requirements,the influence of Nb content on the GFA of Fe_(57)Cr_(10)Zr_(8)B_(18)Mo_(7-x)Nb_(x)(x=1-5,at.%)alloys was investigated,as Nb has positive roles in GFA and thermal stability of BMGs.The results indicate that a fully amorphous phase in the as-cast samples with 3 mm in diameter is obtained for both the Fe_(57)Cr_(10)Zr_(8)B_(18)Mo_(5)Nb_(2) and Fe_(57)Cr_(10)Zr_(8)B_(18)Mo_(4)Nb_(3) alloys.The corresponding supercooled liquid regions of the two BMGs are 78 K and 71 K,respectively.The mechanism for improving their GFA was analyzed based on the principle of metal solidification,the parameters for glass formation and thermal properties of the alloys.The compression strength and Vicker’s hardness of the two BMGs are 1,950 MPa and 1,310 HV,2,062 MPa and 1,180 HV,respectively.The developed BMGs with high B content,good GFA,and very high hardness can be used as coating materials to the framework for spent nuclear fuels.
基金supported by the National Natural Science Foundation of China(No.51274142)the Natural Science Foundation of Liaoning Province(No.2014028015)the Science&Technology Project of Shenyang City(No.F15-199-1-15)
文摘In this study, in order to investigate the influence of Cr element on the impact fracture process of ductile Ni-resistant alloyed iron at low temperature, different contents of Cr element were added to ductile Ni-resistant(DNR) austenitic alloyed iron. The experimental results show that Cr addition can increase the hardness of the DNR alloyed iron, but it has an destructive effect on low-temperature impact properties. Through the analysis of the dynamic load and absorbed energy of samples with different Cr contents in the impact fracture process, and the comparison of the impact fracture process at room and low temperatures, it reveals that Cr addition into the DNR alloyed iron can facilitate the formation of the carbide mixture in Mn23C6 and Cr23C6 with homogeneous and discontinuous distribution. Meanwhile, Cr addition also can improve the the maximum dynamic load and crack initiation energy at low temperature, but has no obvious effect on the yield behavior of the DNR alloyed iron in the impact fracture process. Compared with the impact crack propagation process at room temperature, the metastable propagation energy at low temperature declines significantly with an increase in Cr content. This is because the micro-cracks that caused by the carbides weaken the matrix, resulting in the decline of impact crack propagation resistance. The fracture analysis results also show that the impact fracture mechanism gradually transforms from ductile to brittle with an increase in Cr content at low temperature. It explains that too much Cr addition can lead to brittle fracture even though the austenitic matrix has a good toughness at low temperature.
基金supported by the National Natural Science Foundation of China(51401129,51371066)China Postdoctoral Science Foundation(2015M571327)the Educational Commission of Liaoning Province(L2014052,LGD2016018)
文摘Arc melting was utilized in this study to produce Zr_(55)Cu_(30)Ni_5Al_(10) alloys under mixed atmospheres with various ratios of high-purity hydrogen to argon. The influences of hydrogen addition on the solidification structure and glass-forming ability of Zr_(55)Cu_(30)Ni_5Al_(10) alloy were determined by examining microstructures in different parts of the cast ingots. The results showed that different degrees of crystallization structures were obtained in the ascast button ingots after arc melting in high-purity Ar, and the cross-sectional solidification morphology of arcmelted ingots was found to consist of crystals with varying from the bottom up. By contrast, there were completely amorphous structures in the middle and upper areas of the as-cast button ingots fabricated by adding 10% H_2 to the high-purity Ar atmosphere. A clear solidification interface was found between the crystal and glass in the ascast button ingots, which indicates that hydrogen addition can enhance the Zr_(55)Cu_(30)Ni_5Al_(10) alloy's glass-forming ability. The precise mechanism responsible for this was also investigated.
文摘目的探讨麻醉管理优化方案结合单孔腹腔镜手术对患者快速康复的影响。方法将68例妇科良性肿瘤患者随机分成对照组和ERAS组,对照组患者采用三孔腹腔镜手术结合常规麻醉管理方案,ERAS组患者采用单孔腹腔镜手术结合优化后的麻醉管理方案。比较2组手术时间、拔管时间、复苏室停留时间、达出院标准时间、术后肛门排气时间、术后住院时间及术后30 min、2 h、12 h、24 h VAS评分。比较2组术后恶心呕吐及切口出血、感染等情况。结果ERAS组手术时间、拔管时间、达出院标准时间、术后肛门排气时间、术后住院时间短于对照组,差异均有统计学意义(P<0.05)。2组复苏室停留时间、恶心呕吐发生率比较,差异无统计学意义(P>0.05)。2组患者术后均无切口出血、感染等情况发生。与对照组比较,ERAS组术后30 min VAS评分更高,其余时间点VAS评分更低(P<0.05)。结论优化后的麻醉管理策略结合单孔腔镜手术能减轻患者痛苦,缩短住院时间,促进患者快速康复。
