The reduction behaviors and characteristics of products of the Fe-Cr-O system （FeCr2O4 and Fe2O3＋Cr2O3） and Fe-Cr-Ni-O system （Fe2O3＋Cr2O3＋NiO） under various conditions were studied. The results show that more ...The reduction behaviors and characteristics of products of the Fe-Cr-O system （FeCr2O4 and Fe2O3＋Cr2O3） and Fe-Cr-Ni-O system （Fe2O3＋Cr2O3＋NiO） under various conditions were studied. The results show that more Fe-Cr or Fe-Cr-Ni solution and less residual carbon content were obtained at higher temperatures and lower initial molar ratio of C to O （nC：nO）. The degree of reduction was highly dependent on both time and temperature, and the residual carbon content greatly increased with increasing nC：nO at each temperature. The products generated during the carbothermic reduction of the Fe-Cr-O system were examined using X-ray diffraction （XRD）. A scanning electron microscope （SEM） coupled with energy dispersive spectrometer was used to observe the microstructure and the distribution of elements in the various phases of the final reduction products of the Fe-Cr-O and Fe-Cr-Ni-O.展开更多
Residual stress plays a vital role in the structural strength and stability. The determination of residual stress at single-point has become mature at present. However, the method to determine residual stress distribu...Residual stress plays a vital role in the structural strength and stability. The determination of residual stress at single-point has become mature at present. However, the method to determine residual stress distribution is still in shortage. For this problem, a finite element approach combined with slot milling method was developed in this study. In the method, firstly a slot is milled on the specimen surface to release the residual stress and then the released displacement field is measured by optical method, such as digital image correlation （DIC）, finally the finite element approach is used to determine the residual stress distribution along the slot. In order to verify the feasibility of the method, it was applied to study the residual stress introduced by shot peening, mainly about the stress distribution along the direction vertical to the shot peened surface. Since the influence depth of shot peening was too small, we utilized focused ion beam （FIB） to determine the microscale residual stress distribution. The result measured by X-ray diffraction （XRD） demonstrated that the method was feasible to determine the residual stress distribution.展开更多
基金Project (51074025) supported by the National Natural Science Foundation of ChinaProject (FRF-SD-12-009A) supported by the Fundamental Research Funds for the Central Universities,China
文摘The reduction behaviors and characteristics of products of the Fe-Cr-O system （FeCr2O4 and Fe2O3＋Cr2O3） and Fe-Cr-Ni-O system （Fe2O3＋Cr2O3＋NiO） under various conditions were studied. The results show that more Fe-Cr or Fe-Cr-Ni solution and less residual carbon content were obtained at higher temperatures and lower initial molar ratio of C to O （nC：nO）. The degree of reduction was highly dependent on both time and temperature, and the residual carbon content greatly increased with increasing nC：nO at each temperature. The products generated during the carbothermic reduction of the Fe-Cr-O system were examined using X-ray diffraction （XRD）. A scanning electron microscope （SEM） coupled with energy dispersive spectrometer was used to observe the microstructure and the distribution of elements in the various phases of the final reduction products of the Fe-Cr-O and Fe-Cr-Ni-O.
基金supported by the National Natural Science Foundation of China(Grant Nos.11672153,11232008 & 11227801)
文摘Residual stress plays a vital role in the structural strength and stability. The determination of residual stress at single-point has become mature at present. However, the method to determine residual stress distribution is still in shortage. For this problem, a finite element approach combined with slot milling method was developed in this study. In the method, firstly a slot is milled on the specimen surface to release the residual stress and then the released displacement field is measured by optical method, such as digital image correlation （DIC）, finally the finite element approach is used to determine the residual stress distribution along the slot. In order to verify the feasibility of the method, it was applied to study the residual stress introduced by shot peening, mainly about the stress distribution along the direction vertical to the shot peened surface. Since the influence depth of shot peening was too small, we utilized focused ion beam （FIB） to determine the microscale residual stress distribution. The result measured by X-ray diffraction （XRD） demonstrated that the method was feasible to determine the residual stress distribution.
