Spark plasma sintering versus hot pressing – densification, bending strength, microstructure, and tribological properties of Ti5Al2.5Fe alloys

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.

Download Full-text

Spark Plasma Sintering and Hot Pressing Sintering of Nanocrystalline WC-10CO-0.8VC

Materials Science Forum ◽

10.4028/www.scientific.net/msf.534-536.1229 ◽

2007 ◽

Vol 534-536 ◽

pp. 1229-1232

Author(s):

Li Hui Zhu ◽

Guang Jie Shao ◽

Yi Xiong Liu ◽

Dave Siddle

Keyword(s):

Relative Density ◽

Spark Plasma Sintering ◽

Hot Pressing ◽

Nanocrystalline Powders ◽

Microstructure And Properties ◽

Plasma Sintering ◽

Spark Plasma ◽

Hot Pressing Sintering

WC-10Co-0.8VC nanocrystalline powders were sintered by spark plasma sintering (SPS) and hot pressing sintering (HPS), and the microstructure and properties were compared. Results show that, sintered at 1300°C, the sample prepared by SPS for only 3 minutes has higher density than that prepared by HPS for 60 minutes. SEM and SPM observation shows SPS at 1200°C has a more uniform and finer microstructure, and most of the WC grains are smaller than 100nm. It has a relative density of 95.1%, HV30 of 1887, and KIC of 11.5 MPam1/2. If a suitable sintering parameter is chosen, SPS is a promising consolidation technique to prepare nanocrystalline WC-10Co-0.8VC with improved properties.

Download Full-text

Mechanical Milling-Assisted Spark Plasma Sintering of Fine-Grained W-Ni-Mn Alloy

Materials ◽

10.3390/ma11081323 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1323 ◽

Cited By ~ 1

Author(s):

Yanlin Pan ◽

Daoping Xiang ◽

Ning Wang ◽

Hui Li ◽

Zhishuai Fan

Keyword(s):

Spark Plasma Sintering ◽

Mechanical Milling ◽

Bending Strength ◽

Sintering Temperature ◽

Interface Fracture ◽

Composite Powders ◽

Fine Grained ◽

Plasma Sintering ◽

Binding Phase ◽

Spark Plasma

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.

Download Full-text

Microstructure and Magnetic Properties of Hot-Pressed and Hot-Deformed Composite Magnets Produced by Spark Plasma Sintering Method

Materials Science Forum ◽

10.4028/www.scientific.net/msf.686.740 ◽

2011 ◽

Vol 686 ◽

pp. 740-744 ◽

Cited By ~ 1

Author(s):

Yi Long Ma ◽

Deng Ming Chen ◽

Qian Shen ◽

Peng Jun Cao

Keyword(s):

Magnetic Properties ◽

Spark Plasma Sintering ◽

Hot Pressing ◽

Magnetic Energy ◽

Pressing Temperature ◽

Energy Product ◽

Plasma Sintering ◽

Spark Plasma ◽

Energy Products ◽

Fe Addition

Bulk isotropic and anisotropic Nd13.5Fe80.4Ga0.5B5.6 and Nd13.5Fe80.4Ga0.5B5.6/Fe magnets were synthesized by applying spark plasma sintering (SPS) technique. The effect of hot-pressing temperature on the magnetic properties of hot-pressed (HP) and hot-deformed (HD) magnets without additive and with 5% Fe addition was investigated. With increasing sintering temperature for HP magnets, the grain grew gradually. For HD magnets, the optimal magnetic properties could be obtained at hot-pressing temperature 680°C due to the development of desired c-axis texture and uniform microstructure, which resulted from the appropriate and uniform grain size in HP magnets. Fe addition could enhance remanence (Br) and magnetic energy products ((BH)m) of HP and HD magnets. However, the maximum magnetic energy product of HD magnets decreased when hot-pressing temperature was higher than 650°C.

Download Full-text

Hot Pressing and Spark Plasma Sintering

Ceramics Science and Technology ◽

10.1002/9783527631940.ch39 ◽

2014 ◽

pp. 189-214

Author(s):

Mats Nygren ◽

Zhijian Shen

Keyword(s):

Spark Plasma Sintering ◽

Hot Pressing ◽

Plasma Sintering ◽

Spark Plasma

Download Full-text

Enhanced Mechanical Properties of SiCw/ SiCp-Reinforced Mg Composites Fabricated by Spark Plasma Sintering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.878.83 ◽

2021 ◽

Vol 878 ◽

pp. 83-88

Author(s):

Hideaki Tsukamoto ◽

Chang Sun

Keyword(s):

Mechanical Properties ◽

Melting Point ◽

Spark Plasma Sintering ◽

Bending Strength ◽

Oxide Layers ◽

Plasma Sintering ◽

Spark Plasma

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.

Download Full-text

Enhancing Mechanical Properties of Various Sintered Pellets with Nano-Additives

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.410.62 ◽

2021 ◽

Vol 410 ◽

pp. 62-67

Author(s):

Tien Hiep Nguyen ◽

Yury V. Konyukhov ◽

Van Minh Nguyen

Keyword(s):

Mechanical Properties ◽

Spark Plasma Sintering ◽

Bending Strength ◽

Size Range ◽

Pressureless Sintering ◽

Plasma Sintering ◽

Spark Plasma ◽

Nano Additives ◽

Free Spaces ◽

The Impact

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.

Download Full-text

Effect of Load on the Tribological Properties of Eutectic Al-Si Reinforced n-Al2O3 under Dry Sliding Conditions

Advances in Tribology ◽

10.1155/2020/3761745 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Pranav Dev Srivyas ◽

M.S. Charoo

Keyword(s):

Friction Coefficient ◽

Wear Rate ◽

Spark Plasma Sintering ◽

Tribological Properties ◽

High Load ◽

Dry Sliding ◽

Advanced Composite ◽

Plasma Sintering ◽

Spark Plasma ◽

Composite Samples

Advanced composites are the materials of the new generation. Hence, the focus of the study is to determine the tribological properties of the eutectic Al-Si alloy reinforced with (2, 4, 6, 8, and10 wt. %) of n-Al2O3 against chrome-plated steel ball under dry sliding conditions. The novelty of this work is the fabrication of the composite sample with this elemental composition, which is not done before. Spark plasma sintering (SPS) nonconventional fabrication method is used to fabricate advanced composite samples. Friction coefficient (COF) and wear rate of the composite samples were studied under high load, varying from 50 N to 300 N, using the ball-on-disc tribometer configuration, with other parameters such as stroke, frequency, sliding distance, and sliding velocity remaining constant at 2 mm, 30 Hz, 120 meter, and 0.120 m/s, respectively. Reduction in wear volume for the advanced composite was reported in the range 15.45–44.58% compared to the base alloy (eutectic Al-Si alloy). An increase in friction coefficient was reported in the range 28.80–35.65% compared to the base matrix alloy material. It was also reported that the wear rate increases and the friction coefficient of the composite sample decreases with an increase in load for the tribo-pair. It was observed that an increase in the wt. % of reinforcement influences the friction and wear behavior of the composite. Wear mechanism at high load was characterized by plastic deformation, adhesion, delamination, and abrasion wear. For pre- and postcharacterization of surface and worn tracks, scanning electron microscopy (SEM) electron dispersion spectroscopy (EDS), 3D surface profilometer, and optical microscopy were used. This work aimed to investigate the influence of load on the tribological properties of Al-Si eutectic reinforced n-Al2O3 under dry sliding conditions. Its main objective was to provide a new contribution to the tribological behavior of these composites fabricated using the nonconventional spark plasma sintering method.

Download Full-text

Tribological Properties of Ti2AlNb Matrix Composites Containing Few-Layer Graphene Fabricated by Spark Plasma Sintering

Metals ◽

10.3390/met10070924 ◽

2020 ◽

Vol 10 (7) ◽

pp. 924

Author(s):

Wei Wang ◽

Ziru Han ◽

Qingjuan Wang ◽

Baojia Wei ◽

Shewei Xin ◽

...

Keyword(s):

Spark Plasma Sintering ◽

Tribological Properties ◽

Matrix Composites ◽

X Ray Diffraction ◽

Layer Graphene ◽

Plasma Sintering ◽

Ti2alnb Alloy ◽

The Coefficient Of Friction ◽

Spark Plasma ◽

Few Layer Graphene

Ti2AlNb alloys with few-layer graphene were fabricated by spark plasma sintering (SPS) to enhance the tribological properties (TP) of the composite materials. Microstructure characteristics of the original few-layer graphene (FLG), Ti2AlNb powders, and the sintered composites were characterized by X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The experimental results indicated that FLGs were homogeneously distributed in the composites. Tribological results indicated that the coefficient of friction (COF) of the composites was reduced as the content of FLG increased. Compared with the pure Ti2AlNb alloy, the average COF of the composite with 1.0 wt.% FLG was decreased by 9.4% and the wear rate was decreased by 36%. Meanwhile, the microstructures of the worn surface showed that TiC particles and friction layers formed by residual FLGs were present on the surface of the composites after tribological test. It is proposed that Ti2AlNb alloys with FLGs presented the enhanced wear resistance.

Download Full-text