The effect of compatibility on phase morphology and orientation of isotactic polypropylene （iPP） blends under shear stress was investigated via dynamic packing injection molding （DPIM）. The compatibility of iPP bl...The effect of compatibility on phase morphology and orientation of isotactic polypropylene （iPP） blends under shear stress was investigated via dynamic packing injection molding （DPIM）. The compatibility of iPP blended with other polymers, namely, atactic polypropylene （aPP）, octane-ethylene copolymer （POE）, ethylene-propylene-diene rubber （EPDM） and poly（ethylene-co-vinyl acetate） （EVA）, have first been studied using dynamic mechanical analysis （DMA）. These blends were subjected to DPIM, which relies on the application of shear stress fields to the melt/solid interfaces during the packing stage by means of hydraulically actuated pistons. The phase morphology, orientation and mechanical properties of the injection-molded samples were characterized by SEM, 2D WAXS and Instron. For incompatible iPP/EVA blends, a much elongated and deformed EVA particles and a higher degree of iPP chain orientation were observed under the effect of shear. However, for compatible iPP/aPP blends, a less deformed and elongated aPP particles and less oriented iPP chains were deduced. It can be concluded that the compatibility between the components decreases the deformation and orientation in the polymer blends. This is most likely due to the hindering effect, resulting from the molecular entanglement and interaction in the compatible system.展开更多
This paper reports that the nonlinear refractive index of a novel organic optical storage film doped azodiphenylamine polymer is measured by using the Z-scan technique. The nonlinear refractive index up to 3.7× 1...This paper reports that the nonlinear refractive index of a novel organic optical storage film doped azodiphenylamine polymer is measured by using the Z-scan technique. The nonlinear refractive index up to 3.7× 10^-6 cm^2/W induced by thermo-optical effect is obtained. It indicates that the sample has excellent optical non- linear properties. The physical mechanism of the great nonlinear optical effect is analysed and the optical conjugate characteristic is also discussed with degenerate four-wave-mixing. The phase conjugate wave diffracted from the formative refractive index grating in the sample is acquired and its equivalent reflectivity reaches about 22%. On this basis, the reflective wave phase-conjugated mirror system was designed, and the image aberration experienced in propagation in the storage experiment is corrected by using the system.展开更多
Analysis electron microtechnique (AEM) and high resolution electron microtechnique (HREM) studies were conducted on a spray deposition Al 8.5Fe 1.3V 1.7Si(mass fraction, %) alloy to determine the characteristics of th...Analysis electron microtechnique (AEM) and high resolution electron microtechnique (HREM) studies were conducted on a spray deposition Al 8.5Fe 1.3V 1.7Si(mass fraction, %) alloy to determine the characteristics of the intermetallic phases. The results show that the striking characteristics of the microstructures in as deposited and as extruded alloys indicate the presence of a large amounts of homogeneously distributed fine particles and a few coarse particles, while small amount of eutectics consisted of α (Al) and α AlFeSi are found in local zone in as deposited alloy. The fine particle is identified to be bcc α AlFeSi phase, and the coarse particles are monoclinic α Al 13 Fe 4 equilibrium phase, bcc α AlFeSi phase and newly found hexagonal h AlFeSi metastable phase. In α Al 13 Fe 4 , stacking faults on (100) and (001) plane and microtwin on (100) twinning plane are frequently observed. The extra reflection spots in α AlFeSi reflection pattern can be induced by α AlFeSi superstructure. The hexagonal metastable phase transforms to bcc phase, and the compositions of two phases are very similar. A close crystallographic orientation relationship between hexagonal and bcc phases are determined, and HREM image shows that the interface between them is coherent. [展开更多
Copper-manganese-aluminum （CMA） alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their ...Copper-manganese-aluminum （CMA） alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their microstructure can show wide variations. The morphology, crystallography and composition of the phases presented in an as-cast （CMA） alloy of nominal composition Cu-14%Mn-8%Al-3%Fe-2%Ni were investigated using optical, electron optical, and microprobe analytical techniques. The as-cast microstructure consisted of the grains of fcc α and bcc β-phases alongwith intermetallic precipitates of various morphologies. The room temperature microstructure exhibited four different types of precipitates inside the α-grains： the ＇large＇ dendritic-shaped particles and the cuboid-shaped precipitates, which were rich in Fe and Mn and had an fcc structure, while the ＇small＇ dendritic-shaped particles and the globular precipitates were based on FeaAI and had DO3 structure. These four different morphologies of intermetallic precipitates exhibited discrete orientation-relationships with the α-matrix. The β-grains only contained very small cuboid shaped precipitates, which could only be resolved through transmission electron microscopy. These precipitates were found to be based on Fe3Al and had the DO3 structure.展开更多
By means of crystallite orientation distribution function (ODF) analysis, the influence on orientation variant selection of cold rolling reductions, recrystallization annealing and cooling rates during α→β→α cycl...By means of crystallite orientation distribution function (ODF) analysis, the influence on orientation variant selection of cold rolling reductions, recrystallization annealing and cooling rates during α→β→α cyclic phase transformation treatments in cold rolled titanium sheet has been investigated. The results show that, cold rolling reduction and annealing treatment both have a great effect on the formation of phase transformation textures.No variant selection occurs in cold rolled and recrystallization annealed titanium sheet which resulte in a more randomly distributed texture.The phase transformation texture formed α→β→α transformation is inherited after 3 cycles of α→β→α phase transformation. The cooling rates during phase transformation have little effect on orientation variant selection.展开更多
This work establishes a temperature-controlled sequence function, and a new multi-phase-field model, for liquid- solid-solid multi-phase transformation by coupling the liquid-solid phase transformation model with the ...This work establishes a temperature-controlled sequence function, and a new multi-phase-field model, for liquid- solid-solid multi-phase transformation by coupling the liquid-solid phase transformation model with the solid-solid phase transformation model. Taking an Fe-C alloy as an example, the continuous evolution of a multi-phase transformation is simulated by using this new model. In addition, the growth of grains affected by the grain orientation of the parent phase （generated in liquid-solid phase transformation） in the solid-solid phase transformation is studied. The results show that the morphology of ferrite grains which nucleate at the boundaries of the austenite grains is influenced by the orientation of the parent austenite grains. The growth rate of ferrite grains which nucleate at small-angle austenite grain boundaries is faster than those that nucleate at large-angle austenite grain boundaries. The difference of the growth rate of ferrites grains in different parent phase that nucleate at large-angle austenite grain boundaries, on both sides of the boundaries, is greater than that of ferrites nucleating at small-angle austenite grain boundaries.展开更多
<span style="font-family:Verdana;">Thermal comfort is one of the most important requirements that scientists and building designers must meet to ensure the indoor air quality knowing its importance on ...<span style="font-family:Verdana;">Thermal comfort is one of the most important requirements that scientists and building designers must meet to ensure the indoor air quality knowing its importance on productivity and the health of occupants. However, it has never been of great concern for architects and architectural historians and seldom explores it. Buildings are the large consumer of the most energy consumption (around 40% worldwide) and generate around 35% of GHGs like CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> that leads to extreme climate change. Hence, general and specific eco-friendly solutions in the field of building construction are required. Analysis of this study shows that air conditioning consumption can be significantly reduced thanks to the compressed earth bricks and by taking into account the climate and the orientation of the facades. However, this paper establishes viable low-cost option of building energy consumption while maintaining the thermal comfort and good indoor air quality. This work explains the effect of a single residential room orientation, by reducing </span><span style="font-family:Verdana;">the thermal amplitude, and improving the thermal phase shift in Ouagadougou</span><span style="font-family:Verdana;"> climate conditions in April. Internal temperature was modelled with 8 cardinal orientations. The result corresponds to a decrease of thermal amplitude </span><span style="font-family:Verdana;">damping greater than 4<span style="white-space:nowrap;">°</span>C between East-West and North-South sides and, with a thermal phase shift of 4</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">hours</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">30</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">minutes between the Nord and West walls.</span>展开更多
By means of TEM technique the orientation relationships of cementite, precipitated from islands of granular bainite during tempering, with ferrite have been observed. By calculating the eigenvalues and eigenvectors o...By means of TEM technique the orientation relationships of cementite, precipitated from islands of granular bainite during tempering, with ferrite have been observed. By calculating the eigenvalues and eigenvectors of transformation matrix, Isaichev relationship has been analyzed. The results indicate that Isaichev relationship is indeed the sum of Kurdjumov-Sachs relationship and Pitsch relationship, so the viewpoint that the cementite with Isaichev relationship precipitates from austenite, instead of ferrite, was confirmed. Moreover, the matrix calculation shows that three reported orientation relationships among austenite, ferrite and cementite in pearlitic transformation cannot be simultaneously valid. (Edited author abstract) 4 Refs.展开更多
In this paper, mathematical models and FEA formulation for implementing heat treatment process simulation were given out. The various coupling effects were treated. The object-oriented methodology of developing heat t...In this paper, mathematical models and FEA formulation for implementing heat treatment process simulation were given out. The various coupling effects were treated. The object-oriented methodology of developing heat treatment simulation was explored. The framework of simulating programs was outlined. The main C++ classes were developed, some important member functions were implemented. The present research work shows that using object-oriented method can greatly reduce the amount of coding. The programs are clear in conception, easy to test, modify and expand. By using the methodology introduced in this paper, one heat treatment process three dimensional simulation tool was developed.展开更多
基金This work was financially supported by the National Natural Science Foundation of China (Nos. 20404008, 50373030 and 20490220) the Ministry of Education of China (No. 104154).
文摘The effect of compatibility on phase morphology and orientation of isotactic polypropylene （iPP） blends under shear stress was investigated via dynamic packing injection molding （DPIM）. The compatibility of iPP blended with other polymers, namely, atactic polypropylene （aPP）, octane-ethylene copolymer （POE）, ethylene-propylene-diene rubber （EPDM） and poly（ethylene-co-vinyl acetate） （EVA）, have first been studied using dynamic mechanical analysis （DMA）. These blends were subjected to DPIM, which relies on the application of shear stress fields to the melt/solid interfaces during the packing stage by means of hydraulically actuated pistons. The phase morphology, orientation and mechanical properties of the injection-molded samples were characterized by SEM, 2D WAXS and Instron. For incompatible iPP/EVA blends, a much elongated and deformed EVA particles and a higher degree of iPP chain orientation were observed under the effect of shear. However, for compatible iPP/aPP blends, a less deformed and elongated aPP particles and less oriented iPP chains were deduced. It can be concluded that the compatibility between the components decreases the deformation and orientation in the polymer blends. This is most likely due to the hindering effect, resulting from the molecular entanglement and interaction in the compatible system.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 19834030 and 50533010）.
文摘This paper reports that the nonlinear refractive index of a novel organic optical storage film doped azodiphenylamine polymer is measured by using the Z-scan technique. The nonlinear refractive index up to 3.7× 10^-6 cm^2/W induced by thermo-optical effect is obtained. It indicates that the sample has excellent optical non- linear properties. The physical mechanism of the great nonlinear optical effect is analysed and the optical conjugate characteristic is also discussed with degenerate four-wave-mixing. The phase conjugate wave diffracted from the formative refractive index grating in the sample is acquired and its equivalent reflectivity reaches about 22%. On this basis, the reflective wave phase-conjugated mirror system was designed, and the image aberration experienced in propagation in the storage experiment is corrected by using the system.
文摘Analysis electron microtechnique (AEM) and high resolution electron microtechnique (HREM) studies were conducted on a spray deposition Al 8.5Fe 1.3V 1.7Si(mass fraction, %) alloy to determine the characteristics of the intermetallic phases. The results show that the striking characteristics of the microstructures in as deposited and as extruded alloys indicate the presence of a large amounts of homogeneously distributed fine particles and a few coarse particles, while small amount of eutectics consisted of α (Al) and α AlFeSi are found in local zone in as deposited alloy. The fine particle is identified to be bcc α AlFeSi phase, and the coarse particles are monoclinic α Al 13 Fe 4 equilibrium phase, bcc α AlFeSi phase and newly found hexagonal h AlFeSi metastable phase. In α Al 13 Fe 4 , stacking faults on (100) and (001) plane and microtwin on (100) twinning plane are frequently observed. The extra reflection spots in α AlFeSi reflection pattern can be induced by α AlFeSi superstructure. The hexagonal metastable phase transforms to bcc phase, and the compositions of two phases are very similar. A close crystallographic orientation relationship between hexagonal and bcc phases are determined, and HREM image shows that the interface between them is coherent. [
文摘Copper-manganese-aluminum （CMA） alloys, containing small additions of Fe, Ni, and Si, exhibit good strength and remarkable corrosion resistance against sea water. The alloys are used in as-cast condition, and their microstructure can show wide variations. The morphology, crystallography and composition of the phases presented in an as-cast （CMA） alloy of nominal composition Cu-14%Mn-8%Al-3%Fe-2%Ni were investigated using optical, electron optical, and microprobe analytical techniques. The as-cast microstructure consisted of the grains of fcc α and bcc β-phases alongwith intermetallic precipitates of various morphologies. The room temperature microstructure exhibited four different types of precipitates inside the α-grains： the ＇large＇ dendritic-shaped particles and the cuboid-shaped precipitates, which were rich in Fe and Mn and had an fcc structure, while the ＇small＇ dendritic-shaped particles and the globular precipitates were based on FeaAI and had DO3 structure. These four different morphologies of intermetallic precipitates exhibited discrete orientation-relationships with the α-matrix. The β-grains only contained very small cuboid shaped precipitates, which could only be resolved through transmission electron microscopy. These precipitates were found to be based on Fe3Al and had the DO3 structure.
文摘By means of crystallite orientation distribution function (ODF) analysis, the influence on orientation variant selection of cold rolling reductions, recrystallization annealing and cooling rates during α→β→α cyclic phase transformation treatments in cold rolled titanium sheet has been investigated. The results show that, cold rolling reduction and annealing treatment both have a great effect on the formation of phase transformation textures.No variant selection occurs in cold rolled and recrystallization annealed titanium sheet which resulte in a more randomly distributed texture.The phase transformation texture formed α→β→α transformation is inherited after 3 cycles of α→β→α phase transformation. The cooling rates during phase transformation have little effect on orientation variant selection.
基金supported by the National Natural Science Foundation of China(Grant Nos.51661020,11504149,and 11364024)
文摘This work establishes a temperature-controlled sequence function, and a new multi-phase-field model, for liquid- solid-solid multi-phase transformation by coupling the liquid-solid phase transformation model with the solid-solid phase transformation model. Taking an Fe-C alloy as an example, the continuous evolution of a multi-phase transformation is simulated by using this new model. In addition, the growth of grains affected by the grain orientation of the parent phase （generated in liquid-solid phase transformation） in the solid-solid phase transformation is studied. The results show that the morphology of ferrite grains which nucleate at the boundaries of the austenite grains is influenced by the orientation of the parent austenite grains. The growth rate of ferrite grains which nucleate at small-angle austenite grain boundaries is faster than those that nucleate at large-angle austenite grain boundaries. The difference of the growth rate of ferrites grains in different parent phase that nucleate at large-angle austenite grain boundaries, on both sides of the boundaries, is greater than that of ferrites nucleating at small-angle austenite grain boundaries.
文摘<span style="font-family:Verdana;">Thermal comfort is one of the most important requirements that scientists and building designers must meet to ensure the indoor air quality knowing its importance on productivity and the health of occupants. However, it has never been of great concern for architects and architectural historians and seldom explores it. Buildings are the large consumer of the most energy consumption (around 40% worldwide) and generate around 35% of GHGs like CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> that leads to extreme climate change. Hence, general and specific eco-friendly solutions in the field of building construction are required. Analysis of this study shows that air conditioning consumption can be significantly reduced thanks to the compressed earth bricks and by taking into account the climate and the orientation of the facades. However, this paper establishes viable low-cost option of building energy consumption while maintaining the thermal comfort and good indoor air quality. This work explains the effect of a single residential room orientation, by reducing </span><span style="font-family:Verdana;">the thermal amplitude, and improving the thermal phase shift in Ouagadougou</span><span style="font-family:Verdana;"> climate conditions in April. Internal temperature was modelled with 8 cardinal orientations. The result corresponds to a decrease of thermal amplitude </span><span style="font-family:Verdana;">damping greater than 4<span style="white-space:nowrap;">°</span>C between East-West and North-South sides and, with a thermal phase shift of 4</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">hours</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">30</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">minutes between the Nord and West walls.</span>
文摘By means of TEM technique the orientation relationships of cementite, precipitated from islands of granular bainite during tempering, with ferrite have been observed. By calculating the eigenvalues and eigenvectors of transformation matrix, Isaichev relationship has been analyzed. The results indicate that Isaichev relationship is indeed the sum of Kurdjumov-Sachs relationship and Pitsch relationship, so the viewpoint that the cementite with Isaichev relationship precipitates from austenite, instead of ferrite, was confirmed. Moreover, the matrix calculation shows that three reported orientation relationships among austenite, ferrite and cementite in pearlitic transformation cannot be simultaneously valid. (Edited author abstract) 4 Refs.
文摘In this paper, mathematical models and FEA formulation for implementing heat treatment process simulation were given out. The various coupling effects were treated. The object-oriented methodology of developing heat treatment simulation was explored. The framework of simulating programs was outlined. The main C++ classes were developed, some important member functions were implemented. The present research work shows that using object-oriented method can greatly reduce the amount of coding. The programs are clear in conception, easy to test, modify and expand. By using the methodology introduced in this paper, one heat treatment process three dimensional simulation tool was developed.
