Densification and Mechanical Property of Nanostructured NiAl Produced by Mechanical-Alloying and Spark-Plasma Sintering

2004 ◽  
Vol 449-452 ◽  
pp. 1101-1104 ◽  
Author(s):  
Ji Soon Kim ◽  
S.-H. Jung ◽  
Young Do Kim ◽  
Chung Hyo Lee ◽  
Young Soon Kwon

Mechanically-alloyed NiAl powder was sintered by Spark-Plasma Sintering (SPS) process. Densification behavior and mechanical property were determined. Above 97% relative density was obtained after sintering at 1150oC for 5min. Crystallite size determined by the Scherrer method was approximately 80 nm. TEM observation revealed a relative larger crystallite size. X-ray diffraction analysis showed that the sintered bodies were composed mainly of NiAl phase together with Ni3Al phase. Sintered NiAl body showed an average Vicker’s hardness of 555Hv, transverse-rupture strength of 1393MPa, 4-point-bending strength of 1100MPa, and fracture toughness of 19.9MPa m-1/2

2014 ◽  
Vol 788 ◽  
pp. 329-333
Author(s):  
Rui Zhou ◽  
Xiao Gang Diao ◽  
Jun Chen ◽  
Xiao Nan Du ◽  
Guo Ding Yuan ◽  
...  

Effects of sintering temperatures on the microstructure and mechanical performance of SPS M3:2 high speed steel prepared by spark plasma sintering was studied. High speed steel sintering curve of continuous heating from ambient temperature to 1200°C was estimated to analyze the sintering processes and sintering temperature range. The sintering temperature within this range was divided into groups to investigate hardness, relative density and microstructure of M3:2 high-speed steel. Strip and quadrate carbides were observed inside the equiaxed grains. SPS sintering temperature at 900°C can lead to nearly full densification with grain size smaller than 20μm. The hardness and bending strength are higher than that of the conventionally powder metallurgy fabricated ones sintered at 1270°C. However, fracture toughness of the high speed steel is lower than that of the conventional powder metallurgy steels. This can be attributed to the shape and distribution of M6C carbides which reduce the impact toughness of high speed steels.


Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1323 ◽  
Author(s):  
Yanlin Pan ◽  
Daoping Xiang ◽  
Ning Wang ◽  
Hui Li ◽  
Zhishuai Fan

Fine-grained W-6Ni-4Mn alloys were fabricated by spark plasma sintering (SPS) using mechanical milling W, Ni and Mn composite powders. The relative density of W-6Ni-4Mn alloy increases from 71.56% to 99.60% when it is sintered at a low temperature range of 1000–1200 °C for 3 min. The spark plasma sintering process of the alloy can be divided into three stages, which clarify the densification process of powder compacts. As the sintering temperature increases, the average W grain size increases but remains at less than 7 µm and the distribution of the binding phase is uniform. Transmission electron microscopy (TEM) observation reveals that the W-6Ni-4Mn alloy consists of the tungsten phase and the γ-(Ni, Mn, W) binding phase. As the sintering temperature increases, the Rockwell hardness and bending strength of alloys initially increases and then decreases. The optimum comprehensive hardness and bending strength of the alloy are obtained at 1150 °C. The main fracture mode of the alloys is W/W interface fracture.


2021 ◽  
Vol 878 ◽  
pp. 83-88
Author(s):  
Hideaki Tsukamoto ◽  
Chang Sun

This study aims to fabricate SiC whisker (w)/ particle (p)-reinforced magnesium (Mg) composites with enhanced mechanical properties using spark plasma sintering (SPS) methods. It has been confirmed that dispersing state of SiCw can be improved by addition of SiCp. However, due to presence of voids and cracks between the oxide layers, surrounding SiCw/p, and Mg matrix in the composites, SiCw with SiCp cannot contribute to enhance the bending strength of Mg matrix. This issue can be tackled by adding low melting point metals such as Sn into the composites to fill the defects in the composites.


2021 ◽  
Vol 410 ◽  
pp. 62-67
Author(s):  
Tien Hiep Nguyen ◽  
Yury V. Konyukhov ◽  
Van Minh Nguyen

The impact of Fe, Co, Ni nano-additives on the density, microhardness and bending strength was investigated for several sintered pellets. Fe, Co, Ni nanopowders (NP) were prepared in the size range 67-94 nm using chemical metallurgy techniques. These powders (0.5 wt. %) were dispersed into three sets of micron powders: Co (+0.5 wt. % Co NP); Fe (+0.5 wt. % Fe NP); Fe+0.5wt. % C (+0.5 wt. % Co and 0.5 wt. % Ni NP). Mixtures were further mixed and processed using a magnetic mill and a turbulent mixer. Sintering was carried out using spark plasma sintering (SPS) as well as pressureless sintering (PS). The densities of sintered pellets were found to increase by 2.5-3% (SPS) and 3-5% (PS) in the presence of nano-additives; corresponding increases in microhardness and bending strength were determined to be 7.9-11.1% and 17.9-38.7%, respectively. These results are discussed in terms enhanced packing due to interparticle sliding and the filling of free spaces with the nanodisperse phase.


2021 ◽  
Vol 1033 ◽  
pp. 93-97
Author(s):  
Tanapon Tansiranon ◽  
Katsuyoshi Kondoh ◽  
Kazuhiro Ishikawa ◽  
Yoji Miyajima ◽  
Anak Khantachawana

This paper aims to investigate effect of spark plasma sintering temperature on mechanical property of Ti + ZrO2. The samples were prepared by SPS system with the different sintering temperature containing 900, 1,000, and 1,100 oC under the pressing pressure of 30 MPa in vacuum. The results show that hardness of Ti + 2 wt.% ZrO2 alloy increases with increasing sintering temperature. The highest hardness was 363 HV while suitable temperature for sintering Ti + 2 wt.% ZrO2 alloy was 1,100 oC. Further, the microstructure and crystal structure of all samples were single-α-phase structure with different in elements dispersion, which was related to amount of lattice expansion in the HCP structure.


2007 ◽  
Vol 336-338 ◽  
pp. 1050-1052 ◽  
Author(s):  
Hai Tao Wu ◽  
Yun Long Yue ◽  
Wei Bing Wu ◽  
Hai Yan Yin

The γ-TiAl intermetallic compounds were produced at the temperature ranging from 850°C to 1050°C by the Spark Plasma Sintering (SPS) process. The effects of sintering temperature and holding time on the mechanical properties of γ-TiAl intermetallic compounds were investigated. The γ-TiAl intermetallic compounds sintered at 1050°C for 10 min showed a high relative density more than 98%, and had the best three-point bending strength of 643MPa, fracture toughness of 12 MPa·m1/2 and microhardness of 560MPa. The microstructural observations indicated typical characteristics of intergranular fracture, which meant the poor ductility of γ-TiAl intermetallic compounds.


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