The effect of ceramic/metal gradient armor's components characteristic on its impact‐resistant characteristic has been investigated by a new modified Alekseevskii‐Tate equation. The following researching work is...
The effect of ceramic/metal gradient armor's components characteristic on its impact‐resistant characteristic has been investigated by a new modified Alekseevskii‐Tate equation. The following researching work is done by the former model [1]: the effect of ceramic layer on the impact‐resistant characteristic, the effect of gradient layer on the impact‐resistant characteristic and the effect of metal layer on the impact‐resistant characteristic.
Extrusion gelation freeform fabrication process is an extrusion-based freeforming technique capable of fabricating complex shaped monolithic ceramic prototypes by the sequential deposition and solidification of cerami...
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Extrusion gelation freeform fabrication process is an extrusion-based freeforming technique capable of fabricating complex shaped monolithic ceramic prototypes by the sequential deposition and solidification of ceramic suspensions from a computer aided design model. In this process, ceramic parts are produced using an extrusion nozzle suitable for extruding ceramic suspensions. In this study, the processing parameters influencing on manufacturing Al2O3 parts were discussed. Air pressure on top of suspensions, rotating speed of screw, nozzle diameter and scan speed are the main factors to influence the dimensional precision of ceramic bodies. By optimizing these processing parameters, the green bodies were fabricated with high precision. The sintered samples with homogenous microstructure and ∼97.6% relative density could be prepared by sintering of these green bodies at 1600°C for 2 hours.
The structural change in phase transition of hybrid （Cl2H25NH3）2MnCl4 was investigated. The temperature and the structures of the phase transition is investigated by thermal gravimetry （TG） and differential scanni...
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The structural change in phase transition of hybrid （Cl2H25NH3）2MnCl4 was investigated. The temperature and the structures of the phase transition is investigated by thermal gravimetry （TG） and differential scanning calorimetry （DSC）, infrared spectrum （IR） and X-ray diffraction （XRD）. The results suggest that the phase transition is reversible and the structural change arises from the conformation change of the organic chain. The interlayer distance increases when the hybrid transforms from low temperature phase to high temperature phase. This is explained by the diffusion of gauche-bond along the organic chains and they move away from each other when the phase transition occurs. Combining the experimental data with theoretical calculation, we propose that organic chain of the hybrid in high temperature phase is the conformation of gauche-bond alternating with trans bond （noted as GTG＇TGTG＇TGTG＇T）.
Two phosphonic acids: dodecylamine-N, N-dimethylenephosphonic acid (DDPA) and dodecylphosphonic acid (DPA), were used to modify zirconia stationary phase in this paper. The result of FTIR and element analysis indicate...
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Two phosphonic acids: dodecylamine-N, N-dimethylenephosphonic acid (DDPA) and dodecylphosphonic acid (DPA), were used to modify zirconia stationary phase in this paper. The result of FTIR and element analysis indicated that DPA adsorbed on zirconia with Lewis acid-base interaction;however, DDPA adsorbed mainly with chelating effect. Apart from the hydrophobicity, DDPA-ZrO2 had cation-exchange and anion-repellent interaction which was useful for the separation of polar compounds.
Sintering behavior, microstructure and microwave dielectric properties of Ba1+x(Mg1/3Nb2/3)O3 (-0.01 [less-than or equal to] x [less-than or equal to] 0.01) were investigated. An improvement of the degree of 1:2 order...
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Sintering behavior, microstructure and microwave dielectric properties of Ba1+x(Mg1/3Nb2/3)O3 (-0.01 [less-than or equal to] x [less-than or equal to] 0.01) were investigated. An improvement of the degree of 1:2 ordering and sinterability was found in Ba-deficient Ba(Mg1/3 Nb2/3)O3 because there existed Ba vacancies. Excessive Ba inhibits the sintering and the degree of 1:2 ordering. It was proposed that excessive Ba exist in grain boundary and inhibit the movement of grain boundary. Therefore, the sintering was restrained. Ba-deficiency had little effect on dielectric constant of Ba(Mg1/3Nb2/3)O3 ceramics. With Ba-deficiency increasing, Qf value decreased drastically.
This paper used amino-terminated polyether, and amino-terminated polyurethane mixture as curing agent to cure the epoxy resin. A series of epoxy elastmors was gotten. The curing products of epoxy elastomers were chara...
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This paper used amino-terminated polyether, and amino-terminated polyurethane mixture as curing agent to cure the epoxy resin. A series of epoxy elastmors was gotten. The curing products of epoxy elastomers were characterized by DSC and FT-IR respectively. The fracture surface morphologies of the cured products were observed by scanning and transmission electron microscopy analysis. The results showed that the impact toughness of the cured products reaches 52.1 kJ/m2 and the elongation of fraction reaches 160% as well as good mechanical properties.
A multi‐particle 2D plane strain model was used to investigate the dynamic compressive properties of ceramic particle reinforced metal matrix composites (MMCs) in this paper. Ceramic particles were simulated as circl...
A multi‐particle 2D plane strain model was used to investigate the dynamic compressive properties of ceramic particle reinforced metal matrix composites (MMCs) in this paper. Ceramic particles were simulated as circles with different diameters, which were randomly and discretely embedded in the matrix. The constitutive relationship of ceramic material was characterized by Johnson‐Holmquist (JH‐2) damage model. The matrix was assumed to be power‐law strain hardening material, coupled with power‐law strain rate hardening. The ceramic/metal interface was assumed to be perfect. The predicted stress‐strain curves by the numerical models agreed well with those of experiments and unit cell analysis formulae developed by Bao and Lin [3]. The effects of overall strain rates and ceramic volume fraction on the dynamic behavior of the composites had been investigated by this numerical model. The effect of particles' distribution on the particles' damage was also discussed. The results show that the distribution and volume fraction of the particles have obvious effect on the particles' damage.
A new micromechanical method, called the Weighted Residual Self‐Consistent Scheme (WRSCS), is developed to study the effective thermal conductivity of particulate composites. WRSCS provides us with a new approach to ...
A new micromechanical method, called the Weighted Residual Self‐Consistent Scheme (WRSCS), is developed to study the effective thermal conductivity of particulate composites. WRSCS provides us with a new approach to the approximation of effective thermal conductivity of particulate composites with arbitrary phase geometry based on the thermal conduction theory of two‐phase materials within the framework of SCS. FE analyses of a generalized multi‐inclusion model and GSCS model are also carried out in the prediction of the effective thermal conductivity at different inclusion volume fractions. Results show that the effective thermal conductivity depends not only on the properties and volume fractions of its constituents, but also on the geometric shape of the particulate.
The synthesis of Ti3AlC2/TiB2 composites was studied by in-situ spark plasma sintering with different volume content of TiB2. Results indicated the bulk Ti3AlC2/TiB2 was fabricated by SPS, which soaked for 8 min under...
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The synthesis of Ti3AlC2/TiB2 composites was studied by in-situ spark plasma sintering with different volume content of TiB2. Results indicated the bulk Ti3AlC2/TiB2 was fabricated by SPS, which soaked for 8 min under a pressure of 30 MPa at 1250°C. The properties of composites was great increased with the addition of TiB2;the Vicker's hardness increased with addition of TiB2 content, the maximum value is 10.4 GPa. The maximum flexural strength and fracture toughness reached maximum value, which were 696 MPa and 6.6 MPa·m1/2 when the volume content of TiB2 was 10%.
A coupled and uncoupled non-linear thermomechanical finite element analysis using ANSYS have been carried out to analyze the heat transfer and associated thermal stresses during different simulated thermal shock proce...
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A coupled and uncoupled non-linear thermomechanical finite element analysis using ANSYS have been carried out to analyze the heat transfer and associated thermal stresses during different simulated thermal shock processes, and the results of two analyses are discussed. It indicates that piezocaloric effect can be neglect when thermal shock intensity is mild and piezocaloric effect should be taken into account when thermal shock intensity is severe.
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