The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction...The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction （XRD）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that the size of Cu-rich phase particles increases, the interspace of Cu-rich phase particles decreases and the density of Curich phases increases with the increase of Cu content during short-time aging （approximately 800 h） at 650℃ for Super 304H steels. During long-time aging （more than 2 000 h） at 650 ℃, Cu-rich phase precipitates sufficiently and the strengthening effect of Cu-rich phase is preferable in Super 304H steel containing Cu of 4%. The strengthening effect of Cu-rich phase in Super 304H steels containing Cu of 2.2% or 5% is weaker than that with Cu of 4% during long-time aging （more than 2 000 h）.展开更多
Porous sintered Ti-Ag compacts with different Ag content were fabricated by powder metallurgy. The associated hydrothermal treatment and the effect on the apatite formation were studied. The results suggested that TiO...Porous sintered Ti-Ag compacts with different Ag content were fabricated by powder metallurgy. The associated hydrothermal treatment and the effect on the apatite formation were studied. The results suggested that TiO was generated under the condition of low vacuum （1 ×10^-2 Pa） during the process of burning out the spacer-holding particles. After hydrothermal treatment, a sub-microscale porous layer was formed at the pore wall surface of the samples. The apatite-inducing ability of hydrothermal treated porous sintered Ti-Ag compacts with different Ag content was evaluated in modified simulated body fluid （SBF）. And the results proved that there is a clear correlation between the apatite-inducing ability and Ag content. The higher Ag content in porous leads to the decrease of Na＋ ions and basic hydroxyl （OH）b amount, resulting in the decline of apatite-inducing ability in the first stage. However, their apatite-inducing ability was not significantly different from that of Ti after two weeks SBF immersing. Hence, the ionic activity should restore with the processing of SBF soaking, as the saturation of Ag effect.展开更多
基金Sponsored by National Science and Technology Support Plan of China (2007BAE51B02)
文摘The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction （XRD）, scanning electron microscope （SEM） and transmission electron microscope （TEM）. The results show that the size of Cu-rich phase particles increases, the interspace of Cu-rich phase particles decreases and the density of Curich phases increases with the increase of Cu content during short-time aging （approximately 800 h） at 650℃ for Super 304H steels. During long-time aging （more than 2 000 h） at 650 ℃, Cu-rich phase precipitates sufficiently and the strengthening effect of Cu-rich phase is preferable in Super 304H steel containing Cu of 4%. The strengthening effect of Cu-rich phase in Super 304H steels containing Cu of 2.2% or 5% is weaker than that with Cu of 4% during long-time aging （more than 2 000 h）.
基金supported by the National Basic Research Program of China("973 Program",Nos.2012CB619102 and 2012CB619100)National Science Fund for Distinguished Young Scholars(Grant No.51225101)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.HEUCFZ1017 and HEUCFR1020)the Natural Science Foundation of Heilongjiang Province,China(No.ZD201012)
文摘Porous sintered Ti-Ag compacts with different Ag content were fabricated by powder metallurgy. The associated hydrothermal treatment and the effect on the apatite formation were studied. The results suggested that TiO was generated under the condition of low vacuum （1 ×10^-2 Pa） during the process of burning out the spacer-holding particles. After hydrothermal treatment, a sub-microscale porous layer was formed at the pore wall surface of the samples. The apatite-inducing ability of hydrothermal treated porous sintered Ti-Ag compacts with different Ag content was evaluated in modified simulated body fluid （SBF）. And the results proved that there is a clear correlation between the apatite-inducing ability and Ag content. The higher Ag content in porous leads to the decrease of Na＋ ions and basic hydroxyl （OH）b amount, resulting in the decline of apatite-inducing ability in the first stage. However, their apatite-inducing ability was not significantly different from that of Ti after two weeks SBF immersing. Hence, the ionic activity should restore with the processing of SBF soaking, as the saturation of Ag effect.
