基于密度泛函理论计算,研究了氢气分子与Ti原子掺杂的镁薄膜表面的相互作用。结果表明,Ti原子替代在镁薄膜表面第二层的位置最稳定。氢气在Ti原子掺杂的镁薄膜表面(Ti原子替代在第二层)的解离势垒下降至0.76e V。第1个氢原子扩散势垒是0...基于密度泛函理论计算,研究了氢气分子与Ti原子掺杂的镁薄膜表面的相互作用。结果表明,Ti原子替代在镁薄膜表面第二层的位置最稳定。氢气在Ti原子掺杂的镁薄膜表面(Ti原子替代在第二层)的解离势垒下降至0.76e V。第1个氢原子扩散势垒是0.11 e V,氢原子离开Ti原子扩散至更远的位置,而不是吸附在Ti原子旁边;催化剂原子不会与先解离的氢气原子成键。研究表明,掺杂Ti的镁薄膜是一种拥有良好性能的储氢材料。展开更多
An innovative physical simulation apparatus, including high speed camera, red thermal imaging system, and mechanical quantity sensor, was used to investigate the friction heat generation and atom diffusion behavior du...An innovative physical simulation apparatus, including high speed camera, red thermal imaging system, and mechanical quantity sensor, was used to investigate the friction heat generation and atom diffusion behavior during Mg-Ti friction welding process. The results show that the friction coefficient mainly experiences two steady stages. The first steady stage corresponds to the Coulomb friction with material abrasion. The second steady stage corresponds to the stick friction with fully plastic flow. Moreover, the increasing rates of axial displacement, temperature and friction coefficient are obviously enhanced with the increase of rotation speed and axial pressure. It can also be found that the there exists rapid diffusion phenomenon in the Mg-Ti friction welding system. The large deformation activated diffusion coefficient is about 105 higher than that activated by thermal.展开更多
研究了Ti-IF无间隙原子钢热轧、冷轧、退火(700、800℃)过程的析出行为与织构。该钢在700℃退火过程中形成的Fe Ti P析出颗粒降低了{111}织构强度,导致r值降低;而800℃退火过程中形成的析出颗粒提高{111}织构强度,强的{111}织构强度增加...研究了Ti-IF无间隙原子钢热轧、冷轧、退火(700、800℃)过程的析出行为与织构。该钢在700℃退火过程中形成的Fe Ti P析出颗粒降低了{111}织构强度,导致r值降低;而800℃退火过程中形成的析出颗粒提高{111}织构强度,强的{111}织构强度增加r值。700℃退火析出物主要为Fe Ti P,800℃退火析出物主要为Ti4C2S2;由于形成Ti4C2S2析出物,使C在再结晶退火过程中很容易从固溶体中析出而形成{111}织构,促使800℃退火时获得良好的成型性。展开更多
Formaldehyde(HCHO) is a common indoor pollutant, long-term exposure to HCHO may harm human health. Its efficient removal at mild conditions is still challenging. The catalytic oxidation of HCHO molecules on a single a...Formaldehyde(HCHO) is a common indoor pollutant, long-term exposure to HCHO may harm human health. Its efficient removal at mild conditions is still challenging. The catalytic oxidation of HCHO molecules on a single atomic catalyst, Ti-decorated Ti3C2O2(Ti/Ti3C2O2) monolayer, is investigated by performing the first principles calculations in this work. It demonstrates that Ti atoms can be easily well dispersed at the form of single atom on Ti3C2O2 monolayer without aggregation. For HCHO catalytic oxidation, both Langmuir-Hinshelwood(LH) and Eley-Rideal(ER) mechanisms are considered. The results show that the step of HCHO dissociative adsorption on Ti/Ti3C2O2 with activated O2 can release high energy of 4.05 e V based on the ER mechanism, which can help to overcome the energy barrier(1.04 e V) of the subsequent reaction steps. The charge transfer from *OH group to CO molecule(dissociated from HCHO) not only promotes *OH group activation but also plays an important role in the H2 O generation along the ER mechanism. Therefore, HCHO can be oxidized easily on Ti/Ti3C2O2 monolayer, this work could provide significant guidance to develop effective non-noble metal catalysts for HCHO oxidation and broaden the applications of MXene-based materials.展开更多
Anodic oxide films of titanium alloy Ti-10V-2Fe-3Al were sealed in calcium acetate solution. The morphology and composition of the sealed films were investigated using scanning electron microscopy (SEM), atomic force ...Anodic oxide films of titanium alloy Ti-10V-2Fe-3Al were sealed in calcium acetate solution. The morphology and composition of the sealed films were investigated using scanning electron microscopy (SEM), atomic force microscope (AFM) and energy dispersive spectroscopy (EDS). The results show that the sealing process makes the anodic oxide films more uniform. Elemental calcium is presented through the whole depth of the anodic oxide films. The roughness of the anodic oxide films is reduced after the sealing process. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the corrosion behavior of the anodic oxide films. It is revealed that the sealing process improves the corrosion resistance of the anodic oxide film of titanium alloy Ti-10V-2Fe-3Al.展开更多
文摘基于密度泛函理论计算,研究了氢气分子与Ti原子掺杂的镁薄膜表面的相互作用。结果表明,Ti原子替代在镁薄膜表面第二层的位置最稳定。氢气在Ti原子掺杂的镁薄膜表面(Ti原子替代在第二层)的解离势垒下降至0.76e V。第1个氢原子扩散势垒是0.11 e V,氢原子离开Ti原子扩散至更远的位置,而不是吸附在Ti原子旁边;催化剂原子不会与先解离的氢气原子成键。研究表明,掺杂Ti的镁薄膜是一种拥有良好性能的储氢材料。
基金Projects (51101126, 51071123) supported by the National Natural Science Foundation of ChinaProjects (20110491684, 2012T50817) supported by the China Postdoctoral Science FoundationProject (20110942K) supported by the Open Fund of State Key Laboratory of Powder Metallurgy of Central South University, China
文摘An innovative physical simulation apparatus, including high speed camera, red thermal imaging system, and mechanical quantity sensor, was used to investigate the friction heat generation and atom diffusion behavior during Mg-Ti friction welding process. The results show that the friction coefficient mainly experiences two steady stages. The first steady stage corresponds to the Coulomb friction with material abrasion. The second steady stage corresponds to the stick friction with fully plastic flow. Moreover, the increasing rates of axial displacement, temperature and friction coefficient are obviously enhanced with the increase of rotation speed and axial pressure. It can also be found that the there exists rapid diffusion phenomenon in the Mg-Ti friction welding system. The large deformation activated diffusion coefficient is about 105 higher than that activated by thermal.
文摘研究了Ti-IF无间隙原子钢热轧、冷轧、退火(700、800℃)过程的析出行为与织构。该钢在700℃退火过程中形成的Fe Ti P析出颗粒降低了{111}织构强度,导致r值降低;而800℃退火过程中形成的析出颗粒提高{111}织构强度,强的{111}织构强度增加r值。700℃退火析出物主要为Fe Ti P,800℃退火析出物主要为Ti4C2S2;由于形成Ti4C2S2析出物,使C在再结晶退火过程中很容易从固溶体中析出而形成{111}织构,促使800℃退火时获得良好的成型性。
文摘Formaldehyde(HCHO) is a common indoor pollutant, long-term exposure to HCHO may harm human health. Its efficient removal at mild conditions is still challenging. The catalytic oxidation of HCHO molecules on a single atomic catalyst, Ti-decorated Ti3C2O2(Ti/Ti3C2O2) monolayer, is investigated by performing the first principles calculations in this work. It demonstrates that Ti atoms can be easily well dispersed at the form of single atom on Ti3C2O2 monolayer without aggregation. For HCHO catalytic oxidation, both Langmuir-Hinshelwood(LH) and Eley-Rideal(ER) mechanisms are considered. The results show that the step of HCHO dissociative adsorption on Ti/Ti3C2O2 with activated O2 can release high energy of 4.05 e V based on the ER mechanism, which can help to overcome the energy barrier(1.04 e V) of the subsequent reaction steps. The charge transfer from *OH group to CO molecule(dissociated from HCHO) not only promotes *OH group activation but also plays an important role in the H2 O generation along the ER mechanism. Therefore, HCHO can be oxidized easily on Ti/Ti3C2O2 monolayer, this work could provide significant guidance to develop effective non-noble metal catalysts for HCHO oxidation and broaden the applications of MXene-based materials.
基金Project(51171011)supported by the National Natural Science Foundation of China
文摘Anodic oxide films of titanium alloy Ti-10V-2Fe-3Al were sealed in calcium acetate solution. The morphology and composition of the sealed films were investigated using scanning electron microscopy (SEM), atomic force microscope (AFM) and energy dispersive spectroscopy (EDS). The results show that the sealing process makes the anodic oxide films more uniform. Elemental calcium is presented through the whole depth of the anodic oxide films. The roughness of the anodic oxide films is reduced after the sealing process. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization were used to study the corrosion behavior of the anodic oxide films. It is revealed that the sealing process improves the corrosion resistance of the anodic oxide film of titanium alloy Ti-10V-2Fe-3Al.
