Effect of Sintering Aid on Microstructure and Mechanical Properties of TiB2/TiN Tool Materials

2011 ◽  
Vol 287-290 ◽  
pp. 1933-1937 ◽  
Author(s):  
Mei Lin Gu ◽  
Jian Hua Zhang ◽  
Zhi Wei

TiB2/TiN composites with various content of Ni and Mo as sintering aid were hot-pressed at 1530°C. Effect of the content of sintering aid on microstructure and mechanical properties is investigated. Experimental results show that the fracture toughness of the composites increases consistently with an increase in the sintering aid content, however, the flexural strength gets to the maximum when the content of sintering aid is 10vol%. A new eutectic phase of MoNi can be found in the composites by X-ray diffraction (XRD) when the amount of sintering aid is over 7vol%. Scan electron microscope (SEM) analysis shows that the density of the composites increases consistently with the increasing of the sintering aid. But the abnormal-growth grains can be found and deteriorates the flexural strength in the composite No.4 because of the excessive sintering aid.

2019 ◽  
Vol 54 (6) ◽  
pp. 765-772 ◽  
Author(s):  
Ajay Kumar Vemulapalli ◽  
Rama Murty Raju Penmetsa ◽  
Ramanaiah Nallu ◽  
Rajesh Siriyala

Hydroxyapatite is a very attractive material for artificial implants and human tissue restorations because they accelerate bone growth around the implant. The hydroxyapatite nanocomposites (HAp/TiO2) were produced by using high energy ball milling. X-ray diffraction studies revealed the formation of HAp and TiO2 composites. Cubic-like crystals with boundary morphologies were observed; it was also found that the grain size gradually increased with the increase in TiO2 content. It was found that the mechanical properties (hardness, Young's modulus, fracture toughness, flexural strength, and compression strength)of the composites significantly improved with the addition of TiO2, which was sintered at 1200℃. These properties were then also correlated with the microstructure of the composites. This paper investigates the effect of titania (TiO2 = 0, 5, 10, 15, 20, and 25 wt%) addition on the microstructure and mechanical properties of hydroxyapatite (Ca10(PO4)6(OH)2) nanocomposites.


2012 ◽  
Vol 457-458 ◽  
pp. 1191-1195 ◽  
Author(s):  
Jin Peng Song ◽  
Chuan Zhen Huang ◽  
Bin Zou ◽  
Han Lian Liu ◽  
Jun Wang

TiB2-WC-TiC-Ni composite tool materials were fabricated using Ni as sintering additive by vacuum hot-pressing technique. The microstructure and mechanical properties of the composite were investigated. The composite was analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). The microstructure of TiB2-WC-30wt.%TiC-Ni composite containing fine WC grains, TiC grains and uniform TiB2grains. A lot of pores and coarse grains were found in TiB2-WC-10wt.%TiC-Ni composite. The pores, brittle phases and the coarse grains were harmful to the improvement of the mechanical properties of the composite. The good wettability and the adequate liquid not only inhibited the formation of the pores and the coarse grains, but also strengthened the interface energy among the grains. The flexural strength, fracture toughness and Vickers hardness of TiB2-WC-30wt.%TiC-Ni composite were 996.6±113.6MPa, 7.64±0.28MPa•m1/2and 23.58±0.82GPa, respectively.


2012 ◽  
Vol 500 ◽  
pp. 673-678 ◽  
Author(s):  
Yue Liu ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Bin Zou ◽  
Qiang Shi

Ti (C,N)-TiB2-WC composite ceramic tool materials with sintering aids such as Ni and Mo were fabricated at a temperature of 1550 °C for 1h sintering duration time in vacuum by a hot-press technique. The microstructure and mechanical properties were investigated. The composite ceramic tool materials were analyzed by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). The main phases were composed of Ti (C, N), TiB2, WC and MoC, which indicated that no severe chemical reactions occurred in the composite. The flexural strength, fracture toughness and hardness of Ti (C,N)- 20 wt.%TiB2-WC ceramic material were 795.7 MPa, 6.4 MPa·m1/2 and 19.2 GPa respectively.


2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.


2017 ◽  
Vol 898 ◽  
pp. 638-642 ◽  
Author(s):  
Dong Xu Qiao ◽  
Hui Jiang ◽  
Xiao Xue Chang ◽  
Yi Ping Lu ◽  
Ting Ju Li

A series of refractory high-entropy alloys VTaTiMoAlx with x=0,0.2,0.6,1.0 were designed and produced by vacuum arc melting. The effect of added Al elements on the microstructure and mechanical properties of refractory high-entropy alloys were investigated. The X-ray diffraction results showed that all the high-entropy alloys consist of simple BCC solid solution. SEM indicated that the microstructure of VTaTiMoAlx changes from equiaxial dendritic-like structure to typical dendrite structure with the addition of Al element. The composition of different regions in the alloys are obtained by energy dispersive spectroscopy and shows that Ta, Mo elements are enriched in the dendrite areas, and Al, Ti, V are enriched in inter-dendrite areas. The yield strength and compress strain reach maximum (σ0.2=1221MPa, ε=9.91%) at x=0, and decrease with the addition of Al element at room temperature. Vickers hardness of the alloys improves as the Al addition.


2020 ◽  
Vol 405 ◽  
pp. 379-384
Author(s):  
Joanna Borowiecka-Jamrozek ◽  
Jan Lachowski

The main purpose of this work was to determine the effect of the powder composition on the microstructure and properties of iron-based sinters used as a matrix in diamond tools. The Fe-Cu-Ni sinters obtained from a mixture of ground powders were used for experiments. The influence of manufacturing process parameters on the microstructure and mechanical properties of sinters was investigated. Sintering was performed using hot-pressing technique in a graphite mould. The investigations of obtained sinters included: density, hardness, static tensile test, X-ray diffraction analysis, microstructure and fracture surface observations. The obtained results indicate that the produced sinters have good plasticity and relatively high hardness.


2011 ◽  
Vol 236-238 ◽  
pp. 83-86 ◽  
Author(s):  
Xian Hui Sun

The collagen was blended with polyvinyl alcohol (PVA) with the maximum maintenance of the natural structure as precondition. The apparent viscosity and rheology property of PVA-collagen blended solution were studied. the mechanical properties of the blend membrane formed from PVA-collagen blended solution were also determined. The PVA-collagen blended solution was wet spinned with the sodium sulfate as coagulant to prepare PVA-collagen composite fibers. SEM analysis and X-ray diffraction analysis of the PVA-collagen composite fibers were studied. The results indicated that, blended with PVA, the spinning property and mechanical properties of collagen were improved. The figure of the aim fiber transect structure was similar as the kidney, and it had a uniform size. The crystallization degree of the fiber was 55.7%, and it was increased with the increase of the hot extending temperature and the extending ratio.


2011 ◽  
Vol 704-705 ◽  
pp. 1095-1099
Author(s):  
Peng Liu ◽  
Hao Ran Geng ◽  
Zhen Qing Wang ◽  
Jian Rong Zhu ◽  
Fu Sen Pan ◽  
...  

Effects of AlN addition on the microstructure and mechanical properties of as-cast Mg-Al-Zn magnesium alloy were investigated using optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and tensile testing. Five different samples were made with different amounts of AlN(0wt%, 0.12wt%, 0.30wt%, 0.48wt%, 0. 60wt%). The results show that the phases of as-cast alloy are composed of α-Mg,β-Mg17Al12. The addition of AlN suppressed the precipitation of the β-phase. And, with the increase of AlN content, the microstructure of β-phase was changed from the reticulum to fine grains. When AlN content was up to 0.48wt% in the alloy, the β-phase became most uniform distribution. After adding 0.3wt% AlN to Al-Mg-Zn alloy, the average alloy grain size reduced from 102μm to 35μm ,the tensile strength of alloy was the highest. The average tensile strength increased from 139MPa to 169.91MPa, the hardness increased from 77.7HB to 98.4HB, but the elongation changes indistinctively. However, when more amount of AlN was added, the average alloy grain size did not reduce sequentially and increased to 50μm by adding 0.6wt% AlN and the β-phase became a little more. Keywords: Al-Mg-Zn alloy; AlN; β-Mg17Al12; Tensile strength


2014 ◽  
Vol 59 (1) ◽  
pp. 127-131 ◽  
Author(s):  
J. Bogucka

Abstract The influence of bonding temperature on microstructure and mechanical properties of AA5251 alloy sheets have been analyzed in the paper. The alloy was deformed with the method of accumulative roll bonding (ARB) in various temperature conditions i.e. at ambient temperature up to 5th cycle (ε = 4.0) and using pre-heating of sheet packs at 200°C and 300°C up to 10 cycles (ε = 8.0). The deformed material was subjected to structural observations using TEM, measurements of crystallographic texture with the technique of X-ray diffraction and tensile tests. It was established that the temperature of roll-bonding had a significant effect on the structure evolution and the observed changes of mechanical properties. High refinement of microstructure and optimum mechanical properties were obtained for the material processed at lower temperatures, i.e. at ambient temperature and pre-heating at 200°C. Recovery structure processes occurring during deformation were observed in the alloy bonded with pre-heating at 300°C and therefore mechanical properties were lower than for the alloy bonded at lower temperatures.


2012 ◽  
Vol 05 ◽  
pp. 551-558 ◽  
Author(s):  
A. RAHIMNEZHAD YAZDI ◽  
H.R. BAHARVANDI ◽  
H. ABDIZADEH ◽  
N. EHSANI

In this study Al 2 O 3- SiC nanocomposites have been fabricated by mixing of alumina and silicon carbide nano powders, followed by hot pressing at 1700°C. The mechanical properties and fracture mode of Al 2 O 3- SiC nanocomposites containing different volume fractions (5, 10 and 15%) of nano scale SiC particles were investigated and compared with those of alumina. Al 2 O 3- SiC powders were prepared by planetary milling in isopropanol. Fracture mode of specimens was investigated by means of scanning electron microscopy. Nanocomposites were tougher than alumina when they were hot pressed at the same temperature, and the values of nanocomposite's flexural strength and hardness were higher than those of alumina. Flexural strength, hardness and fracture toughness of the nanocomposites increase by increasing the volume percent of SiC up to 10% and then decrease slightly. The Scanning electron microscopy observations showed that fracture mode changes from intergranular for alumina to transgranular for nanocomposites. Finally X-ray diffraction analysis couldn't detect any chemical reactions between Al 2 O 3 and SiC particles.


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