scholarly journals Modelling the Elements Reaction–Diffusion Behavior on Interface of Ti/Al2O3 Composite Prepared by Hot Pressing Sintering

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 259
Author(s):  
Guopu Shi ◽  
Liu Zhang ◽  
Zhi Wang

Element reaction–diffusion of Ti/Al2O3 composite which was fabricated at various sintering temperatures, holding times, and a sintering pressure of 30 MPa has been discussed in the present research. Results show that the thickness of the reaction layer of the Ti-Al2O3 interface was increased in exponential form in correspondence with the increase of the sintering temperature. Furthermore, according to analysis, the relationship between the thickness of the interface reaction layer, sintering temperature, and heat preservation time acquiring the kinetic equation of interfacial reaction of Ti/Al2O3 composite was d = 182.5exp(−6.6 × 104/RT)t0.48 by linear fitting.

2016 ◽  
Vol 849 ◽  
pp. 391-396 ◽  
Author(s):  
Hao Huang ◽  
Hu Li ◽  
Mao Wen ◽  
Min Juan Wang ◽  
Chuan Xie ◽  
...  

The investigations were focused on the thermochemical and mechanical properties for interface in continuous SiC fiber reinforced TC17 titanium alloy (nominal composition wt.% is Ti-5Al-2Sn-2Zr-4Mo-4Cr) matrix composites (SiCf/Ti). Scanning electron microscope (SEM), transmission electron microscopy (TEM), and electron probe microanalyzer (EPMA) were applied to observe and analyze the interface reaction product at different heat treatment temperatures. In addition, the reaction rate as well as the relationship between the thickness of reaction layer and time was researched. The interfacial strength at different consolidation temperatures was obtained by means of push-out test, while erosion method was employed to measure the residual stress of composites under different consolidation parameters. The results demonstrate that the thickness of interface reaction layer and heat exposure time is accord with the relationship x=kt1/2+x0, and the interface strength is correlated with the thickness of interface reaction layer, which increases with the intensity of interface reaction. Through the comparison, we find that the inner residual stress of the sample consolidated at 940 °C is higher than that of 920 °C.


2017 ◽  
Vol 898 ◽  
pp. 957-963
Author(s):  
Min Juan Wang ◽  
Hao Huang ◽  
Mao Wen ◽  
Hu Li ◽  
Xu Huang ◽  
...  

Continuous SiC fiber reinforced titanium alloy matrix composite (SiCf/Ti) is a potential material in aeronautical field for its excellent mechanical properties. In this work, continuous SiC fiber reinforced TC17 alloy composites (SiCf/TC17) were fabricated by spark plasma sintering (SPS) at different sintering temperatures from 800 to 1000 oC with interval of 50 oC. Consolidated samples were investigated by SEM, EDS and Matrix erosion method. The results showed that the densification degree and the thickness of the interfacial reaction layer increased as the sintering temperature elevated. In addition, the interface reaction layer with typical tooth shape microstructure mainly consisted of TiC and TixSiy, which was quite similar to t that of hot isostatic pressing (HIP) sample. Due to the aggravation of interfacial reaction, there were lots of voids around interfacial layer above 1000 oC, and the residual stress was hardly affected by the sintering temperature. The SiCf/Ti composites can be consolidated at a lower temperature using SPS technology compared with the HIP processing, which is beneficial to the control of the interface reaction together with the reducing of the cost.


Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 727
Author(s):  
Bofang Zhou ◽  
Taohua Li ◽  
Hongxia Zhang ◽  
Junliang Hou

The interface behavior of brazing between Zr-Cu filler metal and SiC ceramic was investigated. Based on the brazing experiment, the formation of brazing interface products was analyzed using OM, SEM, XRD and other methods. The stable chemical potential phase diagram was established to analyze the possible diffusion path of interface elements, and then the growth behavior of the interface reaction layer was studied by establishing relevant models. The results show that the interface reaction between the active element Zr and SiC ceramic is the main reason in the brazing process the interface products are mainly ZrC and Zr2Si and the possible diffusion path of elements in the product formation process is explained. The kinetic equation of interfacial reaction layer growth is established, and the diffusion constant (2.1479 μm·s1/2) and activation energy (42.65 kJ·mol−1) are obtained. The growth kinetics equation of interfacial reaction layer thickness with holding time at different brazing temperatures is obtained.


2014 ◽  
Vol 1061-1062 ◽  
pp. 83-86
Author(s):  
Hong Wu ◽  
De Yi Zheng

In this paper, the effects of different sintering temperature on the microstructure and piezoelectric properties of Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3(PNZZT) ceramic samples were investigated. The Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 ceramics materials was prepared by a conventional mixed oxide method. In the period of the experiment, the relationship between crystallographic phase and microstructure were analyzed by X-ray diffraction(XRD) and scanning electron microscopy(SEM) respectively. The XRD patterns shows that all of the ceramic samples are with a tetragonal perovskite structure. Along with sintering temperature increased and the x is 0.03, the grain size gradually become big. Through this experiment, it has been found that when the x is 0.03 and sintered at 1130°C for 2 h, the grains grow well, the grain-boundary intersection of the sample combined well and the porosity of the ceramics decreased, an excellent comprehensive electrical properties of the Pb(Nb2/3Zn1/3)0.03(Zr52Ti48)0.97O3 samples can be obtained. Its best electrical properties are as follows: dielectric constant (ε) is 1105, dielectric loss(tg) is 0.017, electromechanical coupling coefficient (Kp) is 0.287, piezoelectric constant(d33) is 150PC/N


2018 ◽  
Vol 37 (7) ◽  
pp. 683-691
Author(s):  
Bartek Wierzba ◽  
Wojciech J. Nowak ◽  
Daria Serafin

AbstractThe reaction zones between pure titanium and iron-nickel and pure nickel at 1173 K have been characterized. Two alloys with different initial composition were analyzed. When Ni80Fe20 is used the layer sequence at the reaction interface is: Ni80Fe20 → Ni3Ti → NiTi → NiTi2 →Ti, while for Ni48Fe52 the sequence is: Ni48Fe52 → Ni3Ti → TiFe2 → TiFe → NiTi2 → Ti. The difference is in formation of NiTi, TiFe2 and TiFe phases. The reaction zone remains very thin independently of time due to the fast dissolution rate of Ti in the alloy. The two different elementary chemical interaction processes have been identified in this article, namely the growth of the reaction layers by solid state diffusion and chemical conversion of the compounds by reaction-diffusion in the solid state. The mathematical description combining these processes is presented for description of the diffusion path generated during diffusion process.


1997 ◽  
Vol 1 (2) ◽  
pp. 147-159
Author(s):  
Dirk Meinköhn

For the case of a reaction–diffusion system, the stationary states may be represented by means of a state surface in a finite-dimensional state space. In the simplest example of a single semi-linear model equation given. in terms of a Fredholm operator, and under the assumption of a centre of symmetry, the state space is spanned by a single state variable and a number of independent control parameters, whereby the singularities in the set of stationary solutions are necessarily of the cuspoid type. Certain singularities among them represent critical states in that they form the boundaries of sheets of regular stable stationary solutions. Critical solutions provide ignition and extinction criteria, and thus are of particular physical interest. It is shown how a surface may be derived which is below the state surface at any location in state space. Its contours comprise singularities which correspond to similar singularities in the contours of the state surface, i.e., which are of the same singularity order. The relationship between corresponding singularities is in terms of lower bounds with respect to a certain distinguished control parameter associated with the name of Frank-Kamenetzkii.


2012 ◽  
Vol 44 (3) ◽  
pp. 265-270
Author(s):  
Li-li Wang ◽  
Xiu-Feng Wang ◽  
Xu Ding ◽  
Jian-feng Zhu

The bioglass modified HA-Al2O3 composites were successfully fabricated by mixing HA, synthesized by wet chemical method between precursor materials H3PO4 and Ca(OH)2, with 25wt% Al2O3 and different content of bioglass (5%, 25%, 45%, 65wt%) respectively, with a mole fraction of 53.9%SiO2, 22.6%Na2O, 21.8%CaO, and 1.7wt%P2O5, sintered in air at various temperatures (750-950?C) for 2h. when the content of bioglass is below 45wt% in the composite, HA decomposes completely and transforms to ?-TCP. The main phase in this case are ?-TCP, Al2O3 and Ca3(AlO3)2.When the content of bioglass is above 45wt% in the composite, the decomposition of HA to ?-TCP is suppressed and the main phases in this case are Al2O3 and HA, DCP?CaHPO4? and ?-TCP, which almost have the same chemical composition, forming ternary-glass phase, and have better bioactive than pure HA. It can also be found that at the certain addition of bioglass, the higher sintered temperature, the bigger volume density and flexural strength of the composite are, but when the sintered temperature reaches 950?C, they decrease. This modified HA-Al2O3 composites by calcium silicate glass have a much lower sintering temperature and decrease the production cost much.


2012 ◽  
Vol 512-515 ◽  
pp. 377-381 ◽  
Author(s):  
Jin Rong Lu ◽  
Yang Zhou ◽  
Yong Zheng ◽  
Shi Bo Li ◽  
Zhen Ying Huang ◽  
...  

In this paper, a new type of Ti3SiC2/Cu composites with the volume fractions of 30% Ti3SiC2 particle was prepared by hot pressing and vacuum sintering respectively. The effects of sintering temperature and holding time on the density, resistance and Vickers hardness of Cu-30vol%Ti3SiC2 composite were investigated. The results show that the mechanical properties of the composites prepared by hot pressing are better than that prepared by vacuum sintering. The relative densities of Cu-30vol% Ti3SiC2 composites are rather high in suitable sintering conditions. It achieved 100% for the composites prepared by hot pressing at 930°C for 2h, and 98.4% for the composites prepared by vacuum sintering at 1250°C for 1h. At the same time, the maximum Vickers hardness reached 1735MPa at 900°C by hot pressing. The resistance and Vickers hardness of the composites decreased with an increase in sintering temperature, whereas the density increased. Scanning electron microscope (SEM) and energy-dispersive spectroscopy (EDS) were used to observe the microstructure of the composites. The relationship between microstructure and mechanical properties was discussed.


2021 ◽  
Vol 484 ◽  
pp. 229252
Author(s):  
Marissa Wood ◽  
Xiaosi Gao ◽  
Rongpei Shi ◽  
Tae Wook Heo ◽  
Jose Ali Espitia ◽  
...  

2012 ◽  
Vol 59 (2) ◽  
Author(s):  
Hasmaliza Mohamad ◽  
Hanisah Abdul Rani

Alumina reinforced aluminum is one of metal matrix composite (MMC) systems that can maintain its properties although at high temperature. Among various processes to produce MMC, powder metallurgy is the best method because of its efficiency dispersion of fine alumina particles. In this study, alumina powders were synthesized through sol gel method which is known as one of the ideal method to produce good properties of powders. The performances of synthesized alumina powders were then observed through the fabrication of composite. The percentage of alumina (0wt%, 10wt%, 20wt% and 30wt %) and sintering temperature (500°C and 550°C) were varied in order to observed their effects on the produced composite. Result shows that by increasing the percentage of alumina and sintering temperature, mechanical properties were increased where 30wt% alumina and 550°C sintering temperature give the optimum results. Comparison study by using 30wt% alumina and 550°C sintering temperature on the composite using synthesize and commercial alumina shows similar/comparable properties of composite.


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