HREM study of TiB/Ti interfaces in a TiB-TiC in situ composite

Lü, Weijie; Zhang, Di; Zhang, Xiaonong; Wu, Rui; Sakata, Takao; Mori, Hirotarô

doi:10.1016/s1359-6462(01)00663-7

Cited by 121 publications

(57 citation statements)

References 17 publications

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“…3. This is in agreement with the TEM observations indicating the growth direction of the TiB whiskers is [010], 16,38) which showed that the fiber axis of the TiB whisker is parallel to [010]. In addition, direct extrusion of an as-cast eutectic Ti-6Al-4V-1.55B alloy in the -phase field aligned a majority of the TiB along the extrusion direction.…”

Section: Microstructuresupporting

confidence: 88%

The Elevated-Temperature Creep Behavior of Boron-Modified Ti-6Al-4V Alloys

Boehlert

Chen

2009

Mater. Trans.

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This work investigated the effect of nominal boron (B) additions of 0.1 mass% and 1 mass% on the elevated-temperature (673-728 K) tensile-creep deformation behavior of a Ti-6Al-4V(mass%) alloy for applied stresses between 400-600 MPa. The alloys were evaluated in the as-cast and cast-then-extruded conditions. Boron additions resulted in a dramatic refinement of the as-cast grain size and TiB whisker volume percents of approximately 0.6 and 6.0 for the Ti-6Al-4V-0.1B and Ti-6Al-4V-1B alloys, respectively. The extrusions were performed in thephase field and resulted in the TiB-phase whiskers aligning in the extrusion direction. The creep resistance of the as-cast alloys significantly improved with increased B concentration, where around an order of magnitude decrease in the secondary creep rate was observed between the Ti-6Al-4V-1B and Ti-6Al-4V as-cast alloys. Grain refinement due to the B addition did not deleteriously affect the creep resistance in the temperature and stress ranges considered, where dislocation creep was suggested to be the dominant secondary-creep mechanism. The enhanced creep resistance was attributed to load sharing by the TiB whiskers. For the same nominal B contents, the cast-then-extruded alloys exhibited significantly greater creep resistance and tensile strength than the as-cast alloys. This was explained to be an effect of the -phase texture and the decreased lath spacing in the cast-then-extruded alloys compared with the as-cast alloys. The cast-then-extruded alloys exhibited four times lower lath widths than the as-cast alloys, and the -phase was strongly textured such that the basal plane was predominately oriented perpendicular to the extrusion axis. Comparing the cast-then-extruded alloys, the Ti-6Al-4V alloy exhibited the greatest creep resistance. Overall the -phase consisted of approximately 80% of the microstructure, and the -phase texture appeared to be more dominant to the creep resistance and tensile strength than the small volume percent of TiB-phase in the microstructure. Although B is not necessary to optimize the elevated-temperature creep performance of the Ti-6Al-4V alloy, when boron was present, greater boron additions increased the creep resistance. In-situ creep observations of the surface indicated that the TiB whisker cracking occurred prior to slip and void formation in the þ phases. This was followed by = interface cracking and ductile failure of the þ microstructure.

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Section: Microstructuresupporting

confidence: 88%

The Elevated-Temperature Creep Behavior of Boron-Modified Ti-6Al-4V Alloys

Boehlert

Chen

2009

Mater. Trans.

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“…After the OS is selected and the MF is generated, operation of the network is tested with the use of them (OS & MF). Twenty sample data (data of samples [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] were used from the total of 30, as data sets for network training. Table 3 shows the normalized sample data used for networks training.…”

Section: Resultsmentioning

confidence: 99%

“…[1][2][3][4] The fabrication of TMCs using in-situ technology is simple and does not result in the pollution of an interface. 5,6 TMCs can be reinforced with continuous fibers, whiskers or particles. 7 As is well known, the mechanical properties of the composites depend on matrix, reinforcement and reinforcement/matrix interface, which bonds the formers together.…”

Section: Introductionmentioning

confidence: 99%

Modeling of shot-peening effects on the surface properties of a (TiB + TiC)/Ti–6Al–4V composite employing artificial neural networks

Maleki¹,

Zabihollah²

2016

Mater. Tehnol.

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Titanium matrix composites (TMCs) have wide application prospects in the field of aerospace, automobile and other industries because of their good properties, such as high specific strength, good ductility, and excellent fatigue properties. However, in order to improve their fatigue strength and life, crack initiation and growth at the surface layers must be suppressed using surface treatments. Shot peening (SP) is an effective surface mechanical treatment method widely used in industry which can improve the mechanical properties of a surface. However, artificial neural networks (ANNs) have been used as an efficient approach to predict and optimize the science and engineering problems. In the present study the effects of SP on TMC were modeled by means of ANN and the capability of the ANN in predicting the output parameters is investigated. A back-propagation (BP) error algorithm is developed for the network training. Data of experimental tests on the (TiB + TiC)/Ti-6Al-4V composite are employed in order to train the network. The volume fractions of the reinforcements (TiB + TiC) were 5 % and 8 %. ANN testing is accomplished using different experimental data thaat were not used during the network training. The distance from the surface (depth) and SP intensity are regarded as input parameters and residual stress and hardness of the Ti-6Al-4V before and after the SP and adding reinforcements are gathered as the output parameters of the network. A comparison was made between experimental and predicted data. The predicted results were in good agreement with experimental ones, which indicates that developed neural network can be used for modeling the SP process on TMCs. Keywords: titanium matrix composites, surface treatment, shot peening, artificial neural networks, residual stress, hardness Kompoziti na osnovi titana (TMCs) imajo {iroko mo`nost uporabe na podro~ju letalstva, avtomobilske in druge industrije zaradi njihovih dobrih lastnosti, kot so: velika specifi~na trdnost, dobra duktilnost in odli~na odpornost na utrujanje. Vseeno pa je za pove~anje odpornosti na utrujanje in`ivljenjsko dobo, potrebna povr{inska obdelava, da se zavre nastanek razpok in njihova rast na povr{ini. Hladno povr{insko kovanje (SP) je u~inkovita mehanska metoda, ki se v industriji pogosto uporablja za izbolj{anje mehanskih lastnosti povr{ine. Umetne nevronske mre`e (ANNs) se uporabljajo kot u~inkovit pribli`ek za napovedovanje in optimiranje znanstvenih osnov in in`eniringa tega problema. V {tudiji so bili modelirani vplivi SP na TMC s pomo~jo ANN in preiskovana je bila zmo`nost napovedovanja izhodnih parametrov z ANN. Za usposabljanje mre`e je bil razvit algoritem vzvratnega {irjenja napak (BP). Podatki iz eksperimentalnih preizkusov na (TiB + TiC)/Ti-6Al-4V kompozitu so uporabljeni za usposabljanje mre`e. Volumska dele`a delcev (TiB + TiC) za oja~anje sta bila 5 % in 8 %. ANN preizku{anje je bilo izvedeno z uporabo razli~nih eksperimentalnih podatkov, ki niso bili uporabljeni pri usposabljanju mre`e. Razdalja od povr{ine (globina) in...

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“…Therefore in situ synthesized TMCs have been widely studied. [3][4][5] However, the machining property of these composites is inferior because of the distribution of the reinforcement with high hardness in the soft matrix. It is difficult to machine a workpiece with complex configuration, which restricts the application and development of the composites.…”

Section: Introductionmentioning

confidence: 99%

Effect of Forging Temperature on Microstructure and Mechanical Properties of <I>In Situ</I> (TiB+TiC)/Ti Composites

Lü

Qin

et al. 2006

Mater. Trans.

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In this paper, 5 vol% (TiB+TiC)/Ti-1100(Ti-6Al-2.75Sn-4Zr-0.4Mo-0.45Si) composite were fabricated using in situ technologies between Ti and B 4 C powders. Phase identification was carried out by X-ray diffraction. transus temperature of the composite was measured by metallographic techniques. The composite after ingot breakdown was forged in various temperature ranges. Microstructure of the composite after forging at various temperatures was studied by optical microscopy (OM). Mechanical properties of the composite after forging at various temperatures were evaluated by tensile tests at 873 K. It was found that the transus temperature of the composites was around 100 K higher than that of monolithic Ti-1100 alloy. Different microstructures were obtained after forging at different temperatures. The composite with different microstructures offered different mechanical properties, which was shown in the tensile tests.

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HREM study of TiB/Ti interfaces in a TiB-TiC in situ composite

Cited by 121 publications

References 17 publications

The Elevated-Temperature Creep Behavior of Boron-Modified Ti-6Al-4V Alloys

The Elevated-Temperature Creep Behavior of Boron-Modified Ti-6Al-4V Alloys

Modeling of shot-peening effects on the surface properties of a (TiB + TiC)/Ti–6Al–4V composite employing artificial neural networks

Effect of Forging Temperature on Microstructure and Mechanical Properties of <I>In Situ</I> (TiB+TiC)/Ti Composites

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