The influence of pre-stretching on quench sensitive effect of high strength Al-Zn-Mg-Cu-Zr alloy AA 7085 sheet was investigated by tensile testing at room temperature,transmission electron microscopy(TEM)and different...The influence of pre-stretching on quench sensitive effect of high strength Al-Zn-Mg-Cu-Zr alloy AA 7085 sheet was investigated by tensile testing at room temperature,transmission electron microscopy(TEM)and differential scanning calorimetry(DSC).The water-cooled and aged alloy exhibits higher strength than the air-cooled and aged alloy;2.5%pre-stretching of tensile deformation exerts little effect on strength of water-cooled and aged alloy but increases that of air-cooled and aged one,and therefore the yield strength reduction rate due to slow quenching decreases from about 3.8%to about 1.0%,reducing quench sensitive effect.For the air-cooled alloy,pre-stretching increases the sizes ofη'strengthening precipitates but also increases their quantity and the ratio of diameter to thickness,resulting in enhanced strengthening and higher strength after aging.The reason has been discussed based on microstructure examination by TEM and DSC.展开更多
MoO3 nanobelts （NBs） having different properties have been synthesized via a physical vapor deposition （PVD） method. The crystallographic structures and morphologies of the NBs were characterized by X-ray diffract...MoO3 nanobelts （NBs） having different properties have been synthesized via a physical vapor deposition （PVD） method. The crystallographic structures and morphologies of the NBs were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Electrical measurements were performed and the profound piezoresistive effect in MoO3 experimentally studied and verified. Factors that influence the gauge factor, such as NB size, doping concentration and atmosphere composition, are discussed and analyzed. Gas sensing performance was also tested in devices and it was demonstrated that by applying strain to the gas sensor, its sensing performance could be effectively tuned and enhanced. This study provides the first demonstration of significant piezoresistivity in MoO3 NBs and the first illustration of a generic mechanism by means of which this effect can be coupled with other electronic modulation measures to afford better device performance and broader material functionality.展开更多
基金Project(AA17202007) supported by the Special Funding for Innovation-Driven Development of Guangxi Province,China。
文摘The influence of pre-stretching on quench sensitive effect of high strength Al-Zn-Mg-Cu-Zr alloy AA 7085 sheet was investigated by tensile testing at room temperature,transmission electron microscopy(TEM)and differential scanning calorimetry(DSC).The water-cooled and aged alloy exhibits higher strength than the air-cooled and aged alloy;2.5%pre-stretching of tensile deformation exerts little effect on strength of water-cooled and aged alloy but increases that of air-cooled and aged one,and therefore the yield strength reduction rate due to slow quenching decreases from about 3.8%to about 1.0%,reducing quench sensitive effect.For the air-cooled alloy,pre-stretching increases the sizes ofη'strengthening precipitates but also increases their quantity and the ratio of diameter to thickness,resulting in enhanced strengthening and higher strength after aging.The reason has been discussed based on microstructure examination by TEM and DSC.
文摘MoO3 nanobelts （NBs） having different properties have been synthesized via a physical vapor deposition （PVD） method. The crystallographic structures and morphologies of the NBs were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. Electrical measurements were performed and the profound piezoresistive effect in MoO3 experimentally studied and verified. Factors that influence the gauge factor, such as NB size, doping concentration and atmosphere composition, are discussed and analyzed. Gas sensing performance was also tested in devices and it was demonstrated that by applying strain to the gas sensor, its sensing performance could be effectively tuned and enhanced. This study provides the first demonstration of significant piezoresistivity in MoO3 NBs and the first illustration of a generic mechanism by means of which this effect can be coupled with other electronic modulation measures to afford better device performance and broader material functionality.
