Microstructure and Mechanical Properties of Fe-Cu-Ni Sinters Prepared by Ball Milling and Hot Pressing

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.

2017 ◽  
Vol 749 ◽  
pp. 205-210 ◽  
Author(s):  
Akihiro Nino ◽  
Kaori Morimura ◽  
Shigeaki Sugiyama ◽  
Hitoshi Taimatsu

Powder mixtures of WC–(0–2 mol%) NbC and WC–1.5 mol% NbC–(0–5 mol%) C were sintered at 1800°C using a resistance-heated hot-pressing machine; dense WC–NbC and WC–1.5 mol% NbC–C ceramics were obtained. The relative X-ray diffraction (XRD) peak intensity of W2Css decreased with increasing C amount and disappeared at 5 mol% C. Small amounts of C remained after sintering at 5 mol% C. The WC–1.5 mol% NbC ceramics with 0–3 mol% of added C were composed of equiaxed small granular grains. Large WC grains formed in WC–1.5 mol% NbC ceramics above 4 mol% C. The hardness of WC–NbC ceramics decreased from 25.7 GPa for WC to 23.6 GPa for 2 mol% NbC obtained by NbC addition. The hardness change for WC–1.5 mol% NbC ceramics with up to 3 mol% of added C was small, around 24 GPa. The Vickers hardness of WC–1.5 mol% NbC ceramics above 4 mol% C decreased markedly from 23 to 13 GPa with increasing added C, due to extensive WC grain growth.


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.


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


2013 ◽  
Vol 745-746 ◽  
pp. 700-705
Author(s):  
Huang Liu ◽  
Guo Qiang Luo ◽  
Pin Gan Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang

SiC/Cu composites exhibit low density, low coefficient of thermal expansion and excellent mechanical properties. In this study, Zn of 2 wt. % was added as the sintering activator, and the high volume faction (60%) SiC/Cu composites was fabricated by hot pressing sintering technology. The phase composition and morphology of as-prepare samples were characterized by X-ray diffraction (XRD) system and scanning electron microscopy (SEM) equipped with an energy-dispersive spectroscopy (EDS) system. The as-prepared SiC/Cu composites were dense and uniform as well as void free. The results show that SiC/Cu composites can reach excellent mechanical properties of SiC/Cu composites. With the increase of sintering temperature, Vickers hardness and the bending strength of the samples increased obviously and the as-prepared SiC/Cu composites achieved a maximum Vickers hardness and bending strength respectively of 195MPa and 140MPa.


2013 ◽  
Vol 575-576 ◽  
pp. 156-159
Author(s):  
Dou Qin Ma ◽  
Jing Pei Xie ◽  
Ji Wen Li ◽  
Ai Qin Wang ◽  
Wen Yan Wang ◽  
...  

Cu-3wt. %MoS2-7wt. %Mo and Cu-3wt. %MoS2 composites were prepared by repressing, re-sintering and vacuum hot pressing, respectively. Microstructures were characterized by optical metallographic microscope, EDS, SEM and X-ray diffraction analysis, respectively. The micro hardness, electric conductivity and density of samples were separately measured as well. Results show that the micro hardness of Cu-3wt. % MoS2-7wt. % Mo composites is about 33.3% higher than that of Cu-3wt. %MoS2 composites. The increase in micro hardness is attributed to the presence of Mo. The electric conductivity of Cu-3wt. %MoS2 and Cu-3wt. %MoS2-7wt. % Mo prepared by vacuum hot pressing were 80.6 % and 63.8% IACS, respectively, which is an increase compared with values of 80.2 % and 57.3% IACS of samples obtained by repressing and re-sintering.


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.


2019 ◽  
Vol 26 (1) ◽  
pp. 221-229 ◽  
Author(s):  
Xiaolong Zhou ◽  
Li Chen ◽  
Manmen Liu ◽  
Jie Yu ◽  
Damin Xiong ◽  
...  

AbstractThe AgSnO2NiO composites were prepared by internal oxidation method. The effects of different NiO content on the microstructure and mechanical properties of AgSnO2NiO composites were studied. The phase structure and surface morphology of the prepared AgSnO2NiO materials were characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Metallographic Microscopy (MM). The results showed that the AgSnO2NiO composites with different NiO content can be obtained by the process of preoxidation of AgSn alloy powder and internal oxidation of ingot containing Ni. The agglomeration phenomenon of Ni in the silver matrix was serious, which led to the agglomeration of in-situ generated NiO particles after internal oxidation. After the multi-pass drawing, the SnO2 particles dispersedly distributed in the AgSnO2NiO composites and the NiO particles gradually dispersed from the agglomerated state of the sintered ingot billet. The hardness of the prepared AgSnO2NiO composites increased slightly with the increase of NiO content. The mechanical properties test showed that the introduction of NiO particles significantly improved the tensile strength and elongation of AgSnO2 materials to a certain degree. Adding proper amount of NiO is beneficial to improve the overall performance of AgSnO2 materials.


2018 ◽  
Vol 11 (05) ◽  
pp. 1850033 ◽  
Author(s):  
Shuanglei Li ◽  
Tae-Hyun Nam

In this study, the effect of annealing temperature on microstructure and mechanical properties of a Ti–18Zr–12.5Nb–2Sn (at.%) alloy was investigated by using optical microscopy (OM), X-ray diffraction (XRD) measurement and tensile test. The cold-rolled plate was annealed at temperatures between 773[Formula: see text]K and 1173[Formula: see text]K. Recrystallization occurred in the specimen annealed at 873[Formula: see text]K. Grain size increased from 8[Formula: see text][Formula: see text]m to 80[Formula: see text][Formula: see text]m with increasing temperature from 873[Formula: see text]K to 1173[Formula: see text]K. The ultimate tensile strength decreased from 1590[Formula: see text]MPa to 806[Formula: see text]MPa with increasing annealing temperature from 773[Formula: see text]K to 973[Formula: see text]K, and then showed similar value in the specimens annealed at temperatures from 973[Formula: see text]K to 1173[Formula: see text]K. The fracture strain increased from 3.8% to 41.0% with increasing annealing temperature from 773[Formula: see text]K to 1173[Formula: see text]K due to the recovery and recrystallization. The recovery strain increased with increasing of annealing temperature attributed to the evolution of recrystallization texture.


Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 927
Author(s):  
Xuelei Wang ◽  
Qiufeng Wang ◽  
Zhaojun Dong ◽  
Xiaoqian Zhou ◽  
Xiaoliang Wang ◽  
...  

Ti(C,N)-based cermets with multicomponent ingredients were prepared using vacuum sintering technology. The effect of molding agents, binder phase and sintering temperature on Ti(C,N)-based cermets were studied. The optimum molding performance was obtained by adding 2% polyvinyl alcohol (PVA-1788). The microstructure and mechanical properties of Ti(C,N)-based cermets were investigated. The Ti(C,N)-based cermet with a weight percentage of TiC:TiN:Ni:Co:Mo:WC:Cr3C2:C = 40:10:20:10:7:8:4:1 and sintered at 1450 °C had the optimal mechanical properties. The relative bending strength, Vickers hardness, elastic modulus and wear resistance were 2010 MPa, 15.01 GPa, 483.57 GPa and 27 mg, respectively. Additionally, X-ray diffraction (XRD), backscatter scanning electron microscopy pictures (SEM–BSE), energy dispersive spectrometry (EDS) and optical micrographs of Ti(C,N)-based cermets were characterized.


2013 ◽  
Vol 395-396 ◽  
pp. 201-204
Author(s):  
Feng Wang ◽  
Ji Bao Li ◽  
Ping Li Mao ◽  
Zheng Liu

In order to investigate the ratio of Zn/Y on as-cast Mg-4Zn-xY (x=1, 2, 3 in wt. %), microstructure and mechanical properties are analyzed by scanning electronic microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrum (EDS) and tensile testing. The results indicate that with the decrease of the ratio of Zn/Y, microstructures are refined more greatly and the spheroidization and uniformity coefficient are improved obviously, and the morphologies of second phases are changed from diversity to unity, resulting in an improvement of mechanical properties of alloys.


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