A novel near-net process, gelcasting, was successfully used to prepare larger size 316L stainless steel parts with complex shape. In this study, the effects of process parameters on the viscosity of the slurry and the...A novel near-net process, gelcasting, was successfully used to prepare larger size 316L stainless steel parts with complex shape. In this study, the effects of process parameters on the viscosity of the slurry and the dry green strength were investigated. The results show that gas atomization （GA） powder is more suitable for gelcasting compared with water atomization （WA） powder. The maximum solid loading is 55vo1% for ball-milled slurry with GA powders. And the optimum amounts of monomers （acrylamide （AM）＋methylenebisacrylamide （MBAM）; the mass ratio, 30：1） and initiator in the AM system are 1.8% （based on the weight of metal powder） and 0.8%-1.4% （based on the weight of monomers）, respectively, at which, the maximum green strength obtained is 33.7 MPa. The mechanical properties of the sintered specimen are as follows： ultimate tensile strength, 493 MPa; yield strength, 162 MPa; and HRB, 72.展开更多
A SIMO(single input and multiple output) system of a step-frequency(SF) radar is used.It works in downward-looking spotlight mode and moves within a 2D synthetic plane array.A 3D(three-dimensional) matrix of bistatic ...A SIMO(single input and multiple output) system of a step-frequency(SF) radar is used.It works in downward-looking spotlight mode and moves within a 2D synthetic plane array.A 3D(three-dimensional) matrix of bistatic scattering fields is produced in both the amplitude and phase from a 3D complex-shaped electric-large target above background surface.In numerical simulation,the bidirectional analytic ray tracing(BART) method is applied to calculate bistatic scattering in the SIMO observations from a volumetric target above background rough surface.An improved 3D RMA(range migration algorithm) is then utilized to make the imaging.Its 3D imaging is applied to reconstruct the target profile.As validation and comparison,the scattering fields of some simple targets are computed with comparisons of the BART and FEKO software.The SIMO techniques of imaging and reconstruction for a 3D target,such as a tank-like model over rough surface,are presented.展开更多
文摘A novel near-net process, gelcasting, was successfully used to prepare larger size 316L stainless steel parts with complex shape. In this study, the effects of process parameters on the viscosity of the slurry and the dry green strength were investigated. The results show that gas atomization （GA） powder is more suitable for gelcasting compared with water atomization （WA） powder. The maximum solid loading is 55vo1% for ball-milled slurry with GA powders. And the optimum amounts of monomers （acrylamide （AM）＋methylenebisacrylamide （MBAM）; the mass ratio, 30：1） and initiator in the AM system are 1.8% （based on the weight of metal powder） and 0.8%-1.4% （based on the weight of monomers）, respectively, at which, the maximum green strength obtained is 33.7 MPa. The mechanical properties of the sintered specimen are as follows： ultimate tensile strength, 493 MPa; yield strength, 162 MPa; and HRB, 72.
基金supported by the National Natural Science of Foundation of China (Grant Nos. 60971091 and 41071219)
文摘A SIMO(single input and multiple output) system of a step-frequency(SF) radar is used.It works in downward-looking spotlight mode and moves within a 2D synthetic plane array.A 3D(three-dimensional) matrix of bistatic scattering fields is produced in both the amplitude and phase from a 3D complex-shaped electric-large target above background surface.In numerical simulation,the bidirectional analytic ray tracing(BART) method is applied to calculate bistatic scattering in the SIMO observations from a volumetric target above background rough surface.An improved 3D RMA(range migration algorithm) is then utilized to make the imaging.Its 3D imaging is applied to reconstruct the target profile.As validation and comparison,the scattering fields of some simple targets are computed with comparisons of the BART and FEKO software.The SIMO techniques of imaging and reconstruction for a 3D target,such as a tank-like model over rough surface,are presented.
