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Slip casting and pressureless sintering of Ti3AlC2

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Journal of Advanced Ceramics 2019年第3期8卷 367-376页

作者： Yimin GONG Wubian TIAN Peigen ZHANG Jian CHEN Yamei ZHANG Zhengming SUN Jiangsu Key Laboratory of Advanced Metallic Materials School of Materials Science and EngineeringSoutheast UniversityNanjing211189China Jiangsu Key Laboratory of Construction Materials School of Materials Scienceand EngineeringSoutheast UniversityNanjing211189China

Slip casting and subsequent pressureless sintering(PLS)allow the preparation of complex-shaped and large-sized Ti3AlC2 components for many potential *** behaviors of the suspensions,green compacts,and sintered samples of Ti3AlC2 were studied in this *** optimized condition of 1 wt%of arabic gum as dispersant at pH=10 results in a Ti3AlC2 suspension for slip casting Ti3AlC2 green compacts without macro defects or *** sintering temperature and Al4C3 embedding powder are found to dominate the properties of the sintered Ti3AlC2 *** Ti3AlC2 sample sintered at 1450℃for 1.5 h with Al4C3 embedding powder reaches the best properties,namely 95.3%relative density,hardness of 4.18 GPa,thermal conductivity of 29.11W·m-1·K-1,and electrical resistivity of 0.39μΩ·*** findings in this work may pave the way for the application of MAX phases with large size and complex shape.

关键词： slip casting pressureless sintering(PLS) properties Ti3AlC2

Synthesis of Cr_2AlC from Elemental Powders with Modified pressureless Spark Plasma Sintering

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Journal of Wuhan University of Technology(Materials Science) 2019年第2期34卷 287-292页

作者：葛梦妮 WANG Xiaofan LI Gaiye LU Chen 张建峰 TU Rong College of Mechanics and Materials Hohai University State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology

We introduced a modified pressureless sintering strategy by SPS with a new T-shape die and tapered punches, which helps the evaporation of melted Al and reduces the sample sticking with the inner wall of the die. Thus, the die breaking risk in the sintering process or the de-molding process is avoided at all. At a low temperature and short holding time, a high purity of Cr_2 AlC was obtained in this SPS process from the optimization of different molar ratios of raw materials. Simultaneously, the high porosity of the as-obtained sample was also a distinguishing feature worth noticing. The reaction mechanism for this process was also discussed in detail. This study presented a new venue for future development of high purity "MAX" materials and others related materials by a modified pressureless sintering strategy.

关键词： pressureless spark plasma sintering Cr2AlC reaction mechanism

Effect of the sintering technique on the ferroelectric and d33 piezoelectric coefficients of Bi0.5(Na0.84K0.16)0.5TiO3 ceramic

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Journal of Advanced Ceramics 2019年第2期8卷 278-288页

作者： G.HERNANDEZ-CUEVAS J.R.LEYVA MENDOZA P.E.GARCíA-CASILLAS C.A.RODRíGUEZ GONZáLEZ J.F.HERNANDEZ-PAZ G.HERRERA-PéREZ L.FUENTES-COBAS S.DíAZ DE LA TORRE O.RAYMOND-HERRERA H.CAMACHO-MONTES Instituto de Ingeniería y Tecnología Universidad Autónoma de Ciudad JuárezAv.Del Charro 450 Norte Cd.JuárezChihuahua32310México Centro de Investigación en Materiales Avanzados Miguel de Cervantes 120Chihuahua 31109ChihuahuaMéxico Centro de Investigación e Innovación Tecnológica Instituto Politécnico NacionalCerrada de Cecati s/nAzcapotzalcoSanta Catarina02250Ciudad de MéxicoMéxico Centro de Nanociencias y Nanotecnología Universidad Nacional Autónoma de MéxicoKm.107 Carretera Tijuana-EnsenadaAP.14Ensenada 22860Baja CaliforniaMéxico

In the search of lead-free piezoelectric materials,ceramic processing techniques offer potential tools to increase the piezoelectric and ferroelectric properties in addition to new chemical *** of pure BNKT16(Bi0.5(Na0.84K0.16)0.5TiO3)phase were synthesized by sol–gel method with a low crystallization temperature(750℃).Ceramic samples were sintered by pressureless sintering(PLS),sinter-forging(SF),and spark plasma sintering(SPS)***,morphological,and chemical characterizations were performed by XRD,Raman,EDS,and *** samples by PLS and SF exhibit rod-like grains associated to bismuth *** highest remanent polarization(11.05μC/cm2),coercive field(26.2 kV/mm),and piezoelectric coefficient(165 pC/N)were obtained for SF *** piezoresponse force microscopy(PFM)analysis shows that the crystallites at the nanoscale exhibit piezoelectric phenomenon and the highest piezoelectric response is reported for PLS *** presence of the rhombohedral phase,the increase in grain and crystallite size,and the oriented rod-like inclusions favoring the crystallographic texture are facts that enhance the piezoelectric coefficient for BNKT16 piezoceramics.

关键词： lead-free piezoelectrics sol–gel pressureless sintering (PLS) sinter-forging (SF) spark plasma sintering(SPS) piezoresponse

Microstructure and wear characteristics of ATZ ceramic particle reinforced gray iron matrix surface composites

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China Foundry 2018年第3期15卷 167-172页

作者： Xue Ma Liang-feng Li Fan Zhang Zu-hua Zhang Hao Wang En-ze Wang School of Materials Science and Engineering Southwest University of Science and Technology Chengdu Aerospace Superalloy Technology Co. Ltd Centre for Future Materials University of Southern Queensland

The alumina toughened zirconia(ATZ) ceramic particle reinforced gray iron matrix surface composite was successfully manufactured by pressureless infi ltration. The porous preform played a key role in the infi ltrating progress. The microstructure was observed by scanning electron microscopy(SEM); the phase constitutions was analyzed by X-ray diffraction(XRD); and the hardness and wear resistance of selected specimens were tested by hardness testing machine and abrasion testing machine, respectively. The addition of high carbon ferrochromium powders leads to the formation of white iron during solidifi cation. The wear volume loss rates of ATZ ceramic particle reinforced gray iron matrix surface composite decreases fi rst, and then tends to be stable. The wear resistance of the composite is 2.7 times higher than that of gray iron matrix. The reason is a combination of the surface hardness increase of gray iron matrix and ATZ ceramic particles and alloy carbides protecting effect on gray iron matrix.

关键词： metal-matrix surface composites pressureless infiltrating particle-reinforcement surface alloying wear testing

<ji>In SituSynthesis of Titanium Matrix Composite (Ti-TiB-TiC) through Sintering of TiH2-B4C

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Materials Sciences and Applications 2012年第1期3卷 30-35页

作者： Abdul Jimoh Iakovos Sigalas Mathias Hermann 不详

Fully densified in-situ reinforced (TiB + TiC)-Ti matrix composites have been produced from TiH2-B4C mixtures using pressure less sintering or hot pressing technique. With increasing content of reinforcing components the sintering is retarded. The materials with more than 20 - 30 vol. % were only completely densified by hot pressing technique. Hardness values of the Ti matrix composites produced are up to 5 times higher than that of the sintered pure Ti produced from TiH2. This is caused beside the higher hardness of the inclusions also by hardening the matrix due to solubility of B and C in the titanium.

关键词： Titanium Titanium Hydride Titanium Matrix Composite (TMC) pressureless Sintering In Situ Hardness Matrix Composite Inclusion

A Hyperbolic Eulerian Model for Dilute Two-Phase Suspensions

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Journal of Modern Physics 2011年第9期2卷 997-1011页

作者： Sarah Hank Richard Saurel Olivier Le Metayer 不详

Conventional modeling of two-phase dilute suspensions is achieved with the Euler equations for the gas phase and gas dynamics pressureless equations for the dispersed phase, the two systems being coupled by various relaxation terms. The gas phase equations form a hyperbolic system but the particle phase corresponds to a hyperbolic degenerated one. Numerical difficulties are thus present when dealing with the dilute phase system. In the present work, we consider the addition of turbulent effects in both phases in a thermodynamically consistent way. It results in two strictly hyperbolic systems describing phase’s dynamics. Another important feature is that the new model has improved physical capabilities. It is able, for example, to predict particle dispersion, while the conventional approach fails. These features are highlighted on several test problems involving particles jets dispersion and are compared against experimental data. With the help of a single parameter (a turbulent viscosity), excellent agreement is obtained for various experimental configurations studied by different

关键词： Turbulence Riemann Solver pressureless Gas Dynamics