Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded to...Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded together into 3-layer laminated plates using hot isostatic pressing(HIP).The laminates were ballistically tested and demonstrated superior performance.The microstructure and properties of the laminates were analyzed to determine the effect of the BEPM and HIP processing on the ballistic properties of the layered plates.The effect of porosity in sintered composites on further diffusion bonding of the plates during HIP is analyzed to understand the bonding features at the interfaces between different adjacent layers in the laminate.Exceptional ballistic performance of fabricated structures was explained by a significant reduction in the residual porosity of the BEPM products by their additional processing using HIP,which provides an unprecedented increase in the hardness of the layered composites.It is argued that the combination of the used two technologies,BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.展开更多
(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the...(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the co-precipitation method.Using the synthesized nano-powders as initial material,Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics were fabri-cated by vacuum pre-sintering at different temperatures for 2 h and hot isostatic pressing(HIP)at 1750℃for 3 h in ar-gon.The influence of pre-sintering temperature on the microstructure,optical and luminescence properties was investi-gated.The Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics pre-sintered at 1625℃for 2 h combined with HIP post-treatment show the high-est in-line transmittance of 75.2%at 611 nm.The photoluminescence(PL)and X-ray excited luminescence(XEL)spectra of the Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)transparent ceramics demonstrate a strong red emission peak at 611 nm due to the^(5)D_(0)→^(7)F_(2) transition of Eu^(3+).The PL,PLE and XEL intensities of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics show a trend of first ascending and then descending with the increase of pre-sintering temperature.The thermally stimulated lumines-cence(TSL)curve of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics presents one high peak at 178 K and two peaks with lower intensities at 253 K and 320 K.The peak at 320 K may be related to oxygen vacancies,and the lumines-cence peak at 178 K is related to defects caused by the valence state changes of Eu^(3+)ions.展开更多
The steady development of high-temperature gas-cooled reactors(HTRs) has increased the requirements for the production cost and quality of fuel elements. Green fuel element pressing is one of the key steps to increase...The steady development of high-temperature gas-cooled reactors(HTRs) has increased the requirements for the production cost and quality of fuel elements. Green fuel element pressing is one of the key steps to increase the production capacity. This paper proposes a proprietary vacuum dry-bag isostatic pressing(DIP) apparatus. The structural change of the matrix graphite powder during the DIP process was examined by analyzing the density change of the matrix graphite spheres with pressure. The soft molding process was simulated using the finite element method. The dimensional changes in the spheres during the pressing, carbonization, and purification stages were explored. The performance of the fuel matrix produced by the DIP method was comprehensively examined. The fuel matrix met the technical requirements and its anisotropy was significantly reduced. The DIP method can significantly improve both the production efficiency and quality of fuel elements. This will play a key role in meeting the huge demand for fuel elements of HTRs and molten salt reactors.展开更多
The first wall （FW） is one of the core components in ITER. As the heat sink material, the CuCrZr alloy shall be properly jointed with beryllium and stainless steel. At present, the grains of CuCrZr are prone to coar...The first wall （FW） is one of the core components in ITER. As the heat sink material, the CuCrZr alloy shall be properly jointed with beryllium and stainless steel. At present, the grains of CuCrZr are prone to coarsen seriously in the thermal cycle process of FW manufacturing, which has become a critical issue for ITER parties. To investigate the mirostructure and mechanical properties of the optimized CuCrZr alloy in the first wall fabricating thermal cycle, simulative experiments have been done in this study. The alloy ingot was forged and hot rolled into plates, and then solid solution annealed, cold rolled and aged for strengthening. Several heat treatments were done to the CuCrZr samples, and the changes of microstructure, micro-hardness and tensile strength were investigated. The results indicated that the original elongated grains had changed into equiaxed ones, and the vickers hardness had declined to about 60 after experiencing the process of CuCrZr/316L（N） bi-metallic plate manufacturing, either by hot isostatic pressing at a higher temperature or by explosion welding followed by solution annealing. Joining Be/CuCrZr by hot isostatic pressing acts as an aging process for CuCrZr, so after the simulated heat treatment, the hardness of the alloy increased to about 110 HV and the tensile yield strength at 250℃ rose to about 170 MPa. Meanwhile, the average grain size was controlled below 200μm.展开更多
基金funding from the NATO Agency Science for Peace and Security (#G5787)Ballistic investigations were co-financed by Military University of Technology in Warsaw under research project UGB 829/2023/WATSeparate works made in G.V.Kurdyumov Institute for Metal Physics of N.A.S.of Ukraine were partially financially supported by N.A.S.of Ukraine within the frames of project#III09-18。
文摘Metal matrix composites tiles based on Ti-6Al-4V(Ti64)alloy,reinforced with 10,20,and 40(vol%)of either TiC or TiB particles were made using press-and-sinter blended elemental powder metallurgy(BEPM)and then bonded together into 3-layer laminated plates using hot isostatic pressing(HIP).The laminates were ballistically tested and demonstrated superior performance.The microstructure and properties of the laminates were analyzed to determine the effect of the BEPM and HIP processing on the ballistic properties of the layered plates.The effect of porosity in sintered composites on further diffusion bonding of the plates during HIP is analyzed to understand the bonding features at the interfaces between different adjacent layers in the laminate.Exceptional ballistic performance of fabricated structures was explained by a significant reduction in the residual porosity of the BEPM products by their additional processing using HIP,which provides an unprecedented increase in the hardness of the layered composites.It is argued that the combination of the used two technologies,BEPM and HIP is principally complimentary for the materials in question with the abilities to solve the essential problems of each used individually.
文摘(Gd,Lu)_(2)O_(3)∶Eu scintillation ceramics have promising applications in the high-energy X-ray imaging.Eu0.1Gd0.6Lu1.3O3 nano-powders with pure phase were prepared from the precursor calcined at 1050℃for 4 h by the co-precipitation method.Using the synthesized nano-powders as initial material,Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics were fabri-cated by vacuum pre-sintering at different temperatures for 2 h and hot isostatic pressing(HIP)at 1750℃for 3 h in ar-gon.The influence of pre-sintering temperature on the microstructure,optical and luminescence properties was investi-gated.The Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics pre-sintered at 1625℃for 2 h combined with HIP post-treatment show the high-est in-line transmittance of 75.2%at 611 nm.The photoluminescence(PL)and X-ray excited luminescence(XEL)spectra of the Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)transparent ceramics demonstrate a strong red emission peak at 611 nm due to the^(5)D_(0)→^(7)F_(2) transition of Eu^(3+).The PL,PLE and XEL intensities of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics show a trend of first ascending and then descending with the increase of pre-sintering temperature.The thermally stimulated lumines-cence(TSL)curve of the HIP post-treated Eu_(0.1)Gd_(0.6)Lu_(1.3)O_(3)ceramics presents one high peak at 178 K and two peaks with lower intensities at 253 K and 320 K.The peak at 320 K may be related to oxygen vacancies,and the lumines-cence peak at 178 K is related to defects caused by the valence state changes of Eu^(3+)ions.
基金supported by the National S&T Major Project (No.ZX06901)。
文摘The steady development of high-temperature gas-cooled reactors(HTRs) has increased the requirements for the production cost and quality of fuel elements. Green fuel element pressing is one of the key steps to increase the production capacity. This paper proposes a proprietary vacuum dry-bag isostatic pressing(DIP) apparatus. The structural change of the matrix graphite powder during the DIP process was examined by analyzing the density change of the matrix graphite spheres with pressure. The soft molding process was simulated using the finite element method. The dimensional changes in the spheres during the pressing, carbonization, and purification stages were explored. The performance of the fuel matrix produced by the DIP method was comprehensively examined. The fuel matrix met the technical requirements and its anisotropy was significantly reduced. The DIP method can significantly improve both the production efficiency and quality of fuel elements. This will play a key role in meeting the huge demand for fuel elements of HTRs and molten salt reactors.
基金supported by the International Nuclear Thermonuclear Experimental Reactor(ITER)Specific Program of China(No.2014GB126000)
文摘The first wall （FW） is one of the core components in ITER. As the heat sink material, the CuCrZr alloy shall be properly jointed with beryllium and stainless steel. At present, the grains of CuCrZr are prone to coarsen seriously in the thermal cycle process of FW manufacturing, which has become a critical issue for ITER parties. To investigate the mirostructure and mechanical properties of the optimized CuCrZr alloy in the first wall fabricating thermal cycle, simulative experiments have been done in this study. The alloy ingot was forged and hot rolled into plates, and then solid solution annealed, cold rolled and aged for strengthening. Several heat treatments were done to the CuCrZr samples, and the changes of microstructure, micro-hardness and tensile strength were investigated. The results indicated that the original elongated grains had changed into equiaxed ones, and the vickers hardness had declined to about 60 after experiencing the process of CuCrZr/316L（N） bi-metallic plate manufacturing, either by hot isostatic pressing at a higher temperature or by explosion welding followed by solution annealing. Joining Be/CuCrZr by hot isostatic pressing acts as an aging process for CuCrZr, so after the simulated heat treatment, the hardness of the alloy increased to about 110 HV and the tensile yield strength at 250℃ rose to about 170 MPa. Meanwhile, the average grain size was controlled below 200μm.
