Cracking morphology in the fusion zone of HQ130 high strength steel was researched by 'the y-slit test' and 'three-point bend test', ultrasonic test and microscope. HQ130 and QJ63 high strength steel w...Cracking morphology in the fusion zone of HQ130 high strength steel was researched by 'the y-slit test' and 'three-point bend test', ultrasonic test and microscope. HQ130 and QJ63 high strength steel was welded by Ar+CO2 gas shielded arc welding under the condition without preheating. Experimental results indicated that welding cracks were produced in the partially melted zone of the weld root of HQ130 steel side and propagated parallel to the fusion zone. The cracks were developed alternatively between the weld and the partially melted zone, and are not strictly ruptured at W/F (weld metal/fusion zone) boundary surface. Controlling weld heat input (E) about 16 kJ/cm could make the cracking rate lowest and satisfy the performance requirement of welded joint zone.展开更多
The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercool...The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercooled liquid and liquid states are almost of the same structure. The RDFs (Radius Distribution Function), the first coordination number, the first coordination radius, the correlation radius and atom number of the cluster were calculated for bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in different states. The first coordination sphere radii and the first coordination numbers are 0.312?nm, 11.2 in solid state, 0.301?nm, 10.932 in supercooled liquid region and 0.305?nm, 11.296 in liquid state. The crystal structure of Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy is consisted of several intermetallic compounds which are CuZr 2, Be 2Zr, etc. The reason of formation glass for this alloy is that there is a larger resistance for atoms to rearrange and form intermetallic compounds in a long range order.展开更多
Oriented nanobelts of manganese oxide have been firstly and successfully prepared by a microemulsion technique under controlled circumstances. The samples were characterized by X-ray diffraction (XRD), transmission el...Oriented nanobelts of manganese oxide have been firstly and successfully prepared by a microemulsion technique under controlled circumstances. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM). Influences of sodium chloride and annealed temperature on the synthesis of Mn3O4 nanobelts were investigated. It was found that NaCI is the key factor to synthesize oriented Mn3O4 nanobelts and 827 K is optimum temperature to produce fine nanobelts. Oriented growth mechanism of Mn3O4 nanobelts was discussed.展开更多
X-ray diffraction (XRD) and differential scanning calorimetry (DSC) wereemployed to investigate the influence of Ni content on the crystallization of amorphousZr_(70)Cu_(30-x)Ni_x (atom fraction in percent) alloys. Ex...X-ray diffraction (XRD) and differential scanning calorimetry (DSC) wereemployed to investigate the influence of Ni content on the crystallization of amorphousZr_(70)Cu_(30-x)Ni_x (atom fraction in percent) alloys. Experimental results show that with the Nicontent increasing the activation energies for crystallization of amorphous Zr_(70)Cu_(30-x)Ni_xalloys increase correspondingly, indicating that the thermal stability is greatly improved. All theDSC traces of amorphous Zr_(70)Cu_(30-x)Ni_x alloys exhibit two exothermic peaks, suggesting thatthe crystallization process proceeds via a double-stage mode. The first exothermic peak at lowertemperature mainly corresponds to the precipitation and growth of Zr_2Cu particles, while the secondone corresponds to the precipitation of nano-scale Zr_2Ni phase and crystallization of residualamorphous phase. The mechanism on the crystallization of amorphous Zr_(70)Cu_(30-x)Ni_x alloys wasdiscussed.展开更多
The structure of In-1 %Cu and In-5%Cu (mass fraction) alloy melts werestudied at different temperatures above liquidus by using a high-temperature X-ray diffractometerand were compared with that of pure In melt. Exper...The structure of In-1 %Cu and In-5%Cu (mass fraction) alloy melts werestudied at different temperatures above liquidus by using a high-temperature X-ray diffractometerand were compared with that of pure In melt. Experimental results show that with the addition of 1%Cu or 5% Cu, the thermal contraction phenomenon of atom clusters occurs in melts with thetemperature increasing like pure In melt. With the addition of 1% Cu, the thermal contraction ofatom clusters increases and the contraction is not homogeneous in the whole measurement temperaturerange. The sudden change and noticeable contraction can be found in the range of 280-390 ℃. Thetemperature range of the sudden change is lower than that of pure In melt. With the addition of 5%Cu, the thermal contraction of atom clusters decreases and the contraction is not consistent in thewhole measurement temperature range. The anomalous change can be measured at about 600 ℃. At thesame superheating temperature, the nearest interatomic distance r_1 of the melts containing copperis smaller than that of pure In melt, implying that the cluster structure of melts containing copperis more compact.展开更多
The influence of pre-annealing on thermal stability of the amorphousZr_(70)Cu_(20)Ni_(10) alloy was reported by employing the differential scanning calorimetry (DSC)and high-resolution transmission electron microscopy...The influence of pre-annealing on thermal stability of the amorphousZr_(70)Cu_(20)Ni_(10) alloy was reported by employing the differential scanning calorimetry (DSC)and high-resolution transmission electron microscopy (HRTEM) techniques. It has been observed thatthe supercooled liquid region decreases with increasing the annealing time under isothermalconditions, indicating that the thermal stability of the amorphous Zr_(70)Cu_(20)Ni_(10) alloydecreases gradually. HRTEM observations reveal that there exist some ordered atomic clusters in theamorphous matrix at the relaxation stage. These ordered atomic clusters can be regarded asprecursors for the precipitation of the crystalline phases in the subsequent crystal-lizationprocess. The reasons resulting in the decrease in thermal stability of the amorphousZr_(70)Cu_(20)Ni_(10) alloy with annealing time are discussed through the Gaussian decomposition forthe radial distribution function of the amorphous Zr_(70)Cu_(20)Ni_(10) alloy.展开更多
The stored energy and the energy release during SPD (superplastic deformation) of a Zn-5 Al alloy were studied. The alloy after rolling process gains more stored energy, and the as-rolled specimen can obtain maximum e...The stored energy and the energy release during SPD (superplastic deformation) of a Zn-5 Al alloy were studied. The alloy after rolling process gains more stored energy, and the as-rolled specimen can obtain maximum elongation and minimum flow stress without hot holding treatment before SPD. Experimental results show that stored energy release process is along with SPD process and is also an impetus to SPD. The as-rolled Zn-5Al alloy has 48 J/mol stored energy which was measured with DSC (differential scanning calorimeter) and conforms well to the calculated value. The as-rolled Zn-5Al alloy after SPD with an elongation of 2 500% releases 112 J/mol stored energy. Analysis shows that the strain rate is in direct ratio to the rate of stored energy release.展开更多
The structure of Fe-2.0%C alloy melt was investigated at 1580, 1560, 1540 and 1450℃ by using an X-ray diffractometer respectively. The results showed that with decreasing temperature, the average atoms of cluster, th...The structure of Fe-2.0%C alloy melt was investigated at 1580, 1560, 1540 and 1450℃ by using an X-ray diffractometer respectively. The results showed that with decreasing temperature, the average atoms of cluster, the coordination numbers, the correlation radius and the atom density increased, whereas the pre-peak of the structure factors curve remained almost at the same position. The appearance of the pre-peak indicated that the liquid structure and the solid structure of the Fe-2.0%C alloy were correlated.展开更多
The crystallization kinetics of amorphous Fe68.5Si13.5B9Cu1Nb3C5 (at. pct) melt-spun ribbons were studied by the DSC method in the mode of continuous heating. The apparent activation energy Ep1 and Ep2 (373.07±7....The crystallization kinetics of amorphous Fe68.5Si13.5B9Cu1Nb3C5 (at. pct) melt-spun ribbons were studied by the DSC method in the mode of continuous heating. The apparent activation energy Ep1 and Ep2 (373.07±7.92 and 518.75±21.35 kJ/mol, respectively) derived from the Kissinger plots were calculated by the peak temperatures Tp1, Tp2, which display a strong dependence on the heating rates. The crystallization behavior during isothermal annealing at 823 K for 1, 5, 10 h and 973 K for 5 h were investigated using XRD and TEM. The results show that crystallization behavior becomes completely different from that of FINEMET. It is not bcc α-Fe (Si) but metastable fcc γ-Fe (Si) that participates in the first crystallization step combining the appearance of Fe23B6 and Nb2B. Therefore, the addition of C promotes the combination of Fe and B. Fe3.5B is participated in the second step together with the disappearing of Fe23B6, which indicates that transition Fe23B6→Fe3.5B+Fe2B presumably happens. γ-Fe (Si) with peculiar stability cannot transform into nano-sized α-Fe (Si) crystals until the amorphous ribbons were annealed for 5 h at 973 K.展开更多
文摘Cracking morphology in the fusion zone of HQ130 high strength steel was researched by 'the y-slit test' and 'three-point bend test', ultrasonic test and microscope. HQ130 and QJ63 high strength steel was welded by Ar+CO2 gas shielded arc welding under the condition without preheating. Experimental results indicated that welding cracks were produced in the partially melted zone of the weld root of HQ130 steel side and propagated parallel to the fusion zone. The cracks were developed alternatively between the weld and the partially melted zone, and are not strictly ruptured at W/F (weld metal/fusion zone) boundary surface. Controlling weld heat input (E) about 16 kJ/cm could make the cracking rate lowest and satisfy the performance requirement of welded joint zone.
文摘The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercooled liquid and liquid states are almost of the same structure. The RDFs (Radius Distribution Function), the first coordination number, the first coordination radius, the correlation radius and atom number of the cluster were calculated for bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in different states. The first coordination sphere radii and the first coordination numbers are 0.312?nm, 11.2 in solid state, 0.301?nm, 10.932 in supercooled liquid region and 0.305?nm, 11.296 in liquid state. The crystal structure of Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy is consisted of several intermetallic compounds which are CuZr 2, Be 2Zr, etc. The reason of formation glass for this alloy is that there is a larger resistance for atoms to rearrange and form intermetallic compounds in a long range order.
基金support from the National Natural Science Foundation of China under grant No.550071028Program of Science and Technology Bureau of Qingdao under grant No.03-2-IR-18
文摘Oriented nanobelts of manganese oxide have been firstly and successfully prepared by a microemulsion technique under controlled circumstances. The samples were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM). Influences of sodium chloride and annealed temperature on the synthesis of Mn3O4 nanobelts were investigated. It was found that NaCI is the key factor to synthesize oriented Mn3O4 nanobelts and 827 K is optimum temperature to produce fine nanobelts. Oriented growth mechanism of Mn3O4 nanobelts was discussed.
基金This work is financially supported by the National Natural Science Foundation of China (No. 59871025).
文摘X-ray diffraction (XRD) and differential scanning calorimetry (DSC) wereemployed to investigate the influence of Ni content on the crystallization of amorphousZr_(70)Cu_(30-x)Ni_x (atom fraction in percent) alloys. Experimental results show that with the Nicontent increasing the activation energies for crystallization of amorphous Zr_(70)Cu_(30-x)Ni_xalloys increase correspondingly, indicating that the thermal stability is greatly improved. All theDSC traces of amorphous Zr_(70)Cu_(30-x)Ni_x alloys exhibit two exothermic peaks, suggesting thatthe crystallization process proceeds via a double-stage mode. The first exothermic peak at lowertemperature mainly corresponds to the precipitation and growth of Zr_2Cu particles, while the secondone corresponds to the precipitation of nano-scale Zr_2Ni phase and crystallization of residualamorphous phase. The mechanism on the crystallization of amorphous Zr_(70)Cu_(30-x)Ni_x alloys wasdiscussed.
基金This work was financially supported by the National Natural Science Foundation of China (No. 50231040)the Natural Science Foundation of Shandong Province, China (No. Z2001F02)
文摘The structure of In-1 %Cu and In-5%Cu (mass fraction) alloy melts werestudied at different temperatures above liquidus by using a high-temperature X-ray diffractometerand were compared with that of pure In melt. Experimental results show that with the addition of 1%Cu or 5% Cu, the thermal contraction phenomenon of atom clusters occurs in melts with thetemperature increasing like pure In melt. With the addition of 1% Cu, the thermal contraction ofatom clusters increases and the contraction is not homogeneous in the whole measurement temperaturerange. The sudden change and noticeable contraction can be found in the range of 280-390 ℃. Thetemperature range of the sudden change is lower than that of pure In melt. With the addition of 5%Cu, the thermal contraction of atom clusters decreases and the contraction is not consistent in thewhole measurement temperature range. The anomalous change can be measured at about 600 ℃. At thesame superheating temperature, the nearest interatomic distance r_1 of the melts containing copperis smaller than that of pure In melt, implying that the cluster structure of melts containing copperis more compact.
基金This work is financially supported by the National Natural Science Foundation of China (No.59871025 and 50171006),Hi-tech ResearchDevelopment Program of China(863)(No.2001AA331010)National Major Basic Research Project of China(973)(No.G2000 6720
文摘The influence of pre-annealing on thermal stability of the amorphousZr_(70)Cu_(20)Ni_(10) alloy was reported by employing the differential scanning calorimetry (DSC)and high-resolution transmission electron microscopy (HRTEM) techniques. It has been observed thatthe supercooled liquid region decreases with increasing the annealing time under isothermalconditions, indicating that the thermal stability of the amorphous Zr_(70)Cu_(20)Ni_(10) alloydecreases gradually. HRTEM observations reveal that there exist some ordered atomic clusters in theamorphous matrix at the relaxation stage. These ordered atomic clusters can be regarded asprecursors for the precipitation of the crystalline phases in the subsequent crystal-lizationprocess. The reasons resulting in the decrease in thermal stability of the amorphousZr_(70)Cu_(20)Ni_(10) alloy with annealing time are discussed through the Gaussian decomposition forthe radial distribution function of the amorphous Zr_(70)Cu_(20)Ni_(10) alloy.
基金This work is financially supported by the National Natural Science Foundation of China (Nos. 59871025 and 59871031).
文摘The stored energy and the energy release during SPD (superplastic deformation) of a Zn-5 Al alloy were studied. The alloy after rolling process gains more stored energy, and the as-rolled specimen can obtain maximum elongation and minimum flow stress without hot holding treatment before SPD. Experimental results show that stored energy release process is along with SPD process and is also an impetus to SPD. The as-rolled Zn-5Al alloy has 48 J/mol stored energy which was measured with DSC (differential scanning calorimeter) and conforms well to the calculated value. The as-rolled Zn-5Al alloy after SPD with an elongation of 2 500% releases 112 J/mol stored energy. Analysis shows that the strain rate is in direct ratio to the rate of stored energy release.
基金supported by the National Natural Science Foundations of China(No.50071028 and No.50231040).
文摘The structure of Fe-2.0%C alloy melt was investigated at 1580, 1560, 1540 and 1450℃ by using an X-ray diffractometer respectively. The results showed that with decreasing temperature, the average atoms of cluster, the coordination numbers, the correlation radius and the atom density increased, whereas the pre-peak of the structure factors curve remained almost at the same position. The appearance of the pre-peak indicated that the liquid structure and the solid structure of the Fe-2.0%C alloy were correlated.
基金This work was supported by the National Natural Science Foundation of China under grant No.50271037.
文摘The crystallization kinetics of amorphous Fe68.5Si13.5B9Cu1Nb3C5 (at. pct) melt-spun ribbons were studied by the DSC method in the mode of continuous heating. The apparent activation energy Ep1 and Ep2 (373.07±7.92 and 518.75±21.35 kJ/mol, respectively) derived from the Kissinger plots were calculated by the peak temperatures Tp1, Tp2, which display a strong dependence on the heating rates. The crystallization behavior during isothermal annealing at 823 K for 1, 5, 10 h and 973 K for 5 h were investigated using XRD and TEM. The results show that crystallization behavior becomes completely different from that of FINEMET. It is not bcc α-Fe (Si) but metastable fcc γ-Fe (Si) that participates in the first crystallization step combining the appearance of Fe23B6 and Nb2B. Therefore, the addition of C promotes the combination of Fe and B. Fe3.5B is participated in the second step together with the disappearing of Fe23B6, which indicates that transition Fe23B6→Fe3.5B+Fe2B presumably happens. γ-Fe (Si) with peculiar stability cannot transform into nano-sized α-Fe (Si) crystals until the amorphous ribbons were annealed for 5 h at 973 K.
