High-angle annular dark-field scanning transmission electron microscopy and selected area electron diffraction techniques were used to study the mechanism that underlies the influence of rapid cold-stamping deformatio...High-angle annular dark-field scanning transmission electron microscopy and selected area electron diffraction techniques were used to study the mechanism that underlies the influence of rapid cold-stamping deformation on the fracture behavior of the elongated nanoprecipitated phase in extruded Al−Cu−Mg alloy.Results show that the interface between the long strip-shaped S′phase and the aluminum matrix in the extruded Al−Cu−Mg alloy is flat and breaks during rapid cold-stamping deformation.The breaking mechanisms are distortion and brittle failure,redissolution,and necking.The breakage of the long strip S′phase increases the contact surface between the S′phase and the aluminum matrix and improves the interfacial distortion energy.This effect accounts for the higher free energy of the S′phase than that of the matrix and creates conditions for the redissolution of solute atoms back into the aluminum matrix.The brittle S′phase produces a resolved step during rapid cold-stamping deformation.This step further accelerates the diffusion of solute atoms and promotes the redissolution of the S′phase.Thus,the S′phase necks and separates,and the long strip-shaped S′phase in the extruded Al−Cu−Mg alloy is broken into a short and thin S′phase.展开更多
The electrochemical corrosion,wear,and tribocorrosion behavior of the novel Ti-19Zr-10Nb-1Fe alloy were investigated.The electrochemical corrosion analysis results show that the corrosion resistance of the Ti-19Zr-10N...The electrochemical corrosion,wear,and tribocorrosion behavior of the novel Ti-19Zr-10Nb-1Fe alloy were investigated.The electrochemical corrosion analysis results show that the corrosion resistance of the Ti-19Zr-10Nb-1Fe alloy is better than that of the Ti-6Al-4V alloy under the test conditions in this research.Compared with the static electrochemical corrosion,the corrosion resistance of Ti-19Zr-10Nb-1Fe alloy during tribocorrosion decreases significantly,because the wear accelerates corrosion.The wear volume of Ti-19Zr-10Nb-1Fe alloy is increased with the increase in applied load whether the electrochemical corrosion occurs or not.Due to the acceleration effect of electrochemical corrosion,the wear volume caused by electrochemical corrosion is larger than that without electrochemical corrosion.The results of Wa/Wc are much greater than 10,indicating that during the tribocorrosion process,the material loss caused by mechanical wear is much larger than that caused by electrochemical corrosion.Through SEM observation of the wear morphologies of Ti-19Zr-10Nb-1Fe alloy after tribocorrosion,it can be inferred that the micro-abrasion is the main wear mechanism.The above results show that during the tribocorrosion process,the corrosion accelerates wear,and the wear accelerates corrosion.展开更多
基金Project(19A131)supported by Key Scientific Research Project of Hunan Province,ChinaProject(2019JJ60050)supported by the Natural Science Foundation of Hunan Province,China。
文摘High-angle annular dark-field scanning transmission electron microscopy and selected area electron diffraction techniques were used to study the mechanism that underlies the influence of rapid cold-stamping deformation on the fracture behavior of the elongated nanoprecipitated phase in extruded Al−Cu−Mg alloy.Results show that the interface between the long strip-shaped S′phase and the aluminum matrix in the extruded Al−Cu−Mg alloy is flat and breaks during rapid cold-stamping deformation.The breaking mechanisms are distortion and brittle failure,redissolution,and necking.The breakage of the long strip S′phase increases the contact surface between the S′phase and the aluminum matrix and improves the interfacial distortion energy.This effect accounts for the higher free energy of the S′phase than that of the matrix and creates conditions for the redissolution of solute atoms back into the aluminum matrix.The brittle S′phase produces a resolved step during rapid cold-stamping deformation.This step further accelerates the diffusion of solute atoms and promotes the redissolution of the S′phase.Thus,the S′phase necks and separates,and the long strip-shaped S′phase in the extruded Al−Cu−Mg alloy is broken into a short and thin S′phase.
基金National Natural Science Foundation of China(52071261)。
文摘The electrochemical corrosion,wear,and tribocorrosion behavior of the novel Ti-19Zr-10Nb-1Fe alloy were investigated.The electrochemical corrosion analysis results show that the corrosion resistance of the Ti-19Zr-10Nb-1Fe alloy is better than that of the Ti-6Al-4V alloy under the test conditions in this research.Compared with the static electrochemical corrosion,the corrosion resistance of Ti-19Zr-10Nb-1Fe alloy during tribocorrosion decreases significantly,because the wear accelerates corrosion.The wear volume of Ti-19Zr-10Nb-1Fe alloy is increased with the increase in applied load whether the electrochemical corrosion occurs or not.Due to the acceleration effect of electrochemical corrosion,the wear volume caused by electrochemical corrosion is larger than that without electrochemical corrosion.The results of Wa/Wc are much greater than 10,indicating that during the tribocorrosion process,the material loss caused by mechanical wear is much larger than that caused by electrochemical corrosion.Through SEM observation of the wear morphologies of Ti-19Zr-10Nb-1Fe alloy after tribocorrosion,it can be inferred that the micro-abrasion is the main wear mechanism.The above results show that during the tribocorrosion process,the corrosion accelerates wear,and the wear accelerates corrosion.
