Silver/Diamond Composite Material - Powder Metallurgical Route and Thermo-Physical Properties

2017 ◽  
Vol 742 ◽  
pp. 151-157 ◽  
Author(s):  
Thomas Hutsch ◽  
Thomas Schubert ◽  
Thomas Weißgärber ◽  
Bernd Kieback

To meet the need of high-performance thermal management materials in the field of electronic applications, heat sink materials reinforced with synthetic diamonds have been prepared via powder metallurgy. A matrix of a silver alloy with a silicon content of 0.45 wt.% was chosen out of the prediction of the thickness of a final carbide layer of about 180 nm. The volume content of the diamonds and the diamond size were kept constant. The mixed powders were consolidated by Spark Plasma Sintering (SPS) using different sintering temperatures between 800 and 870 °C with a holding time of 30 min. The maximum thermal conductivity of 680 W/(mK) measured at room temperature and 620 W/(mK) at 275 °C was obtained at 810 °C sintering temperature. The degradation of the most promising sample after one thermal cycle up to 275 °C was determined below 1 percent of the value after sintering.

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040036
Author(s):  
Yongjun Su ◽  
Yunfeng Lin ◽  
Na Zhang ◽  
Deliang Zhang

This work deals with the consolidation of a TiAl alloy powder by spark plasma sintering (SPS). Pre-alloyed powder with a composition of Ti–48Al–2Cr–2Nb (at.%) was consolidated in a SPS furnace at temperatures between 1200[Formula: see text]C and 1325[Formula: see text]C and with a pressure of 50 MPa. The microstructures obtained after SPS depend on the sintering temperature. Tensile tests at room temperature were performed. The alloy SPSed at temperatures not less than 1250[Formula: see text]C exhibits good properties at room temperature.


Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 861 ◽  
Author(s):  
Wang ◽  
Sun ◽  
Du ◽  
Yuan

TiAl alloy has become a key element in aerospace and automotive engine development due to its favorable high temperature mechanical properties and low density. In this paper, high performance TiAl alloy was prepared using atomized Ti-48Al-2Cr-8Nb powder by spark plasma sintering. This paper analyzed the variation of density, microstructure, Vickers hardness, and fracture strength of TiAl alloys prepared with spherical pre-alloyed powder (named as SP powder) and pre-alloyed powder after 12 h of ball milling (named as MP powder) at different sintering temperatures. The results indicate that the density, Vickers hardness, and room temperature (25 °C) bending strength of Ti-48Al-2Cr-8Nb alloy sintered using MP powder, are significantly higher than that of TiAl alloy sintered using SP powder. Specifically, the densification temperature of the MP powder sintered specimen is reduced by 100 °C, the Vickers hardness is increased by 15%, and the room temperature bending strength is increased by 51.9% at a sintering temperature of 1250 °C. The microstructure analysis shows that the Ti-48Al-2Cr-8Nb alloy has the best bending strength when it has a fine grain phase structure.


2007 ◽  
Vol 336-338 ◽  
pp. 864-867
Author(s):  
Wei Ren ◽  
Xue Quan Liu ◽  
Xiao Lin Wang ◽  
Hong Yi Jiang

Polycrystalline samples of Bi2Te3 based alloys were prepared by powder metallurgy processing including a melting-grinding and a sintering procedure of compacted pellets. Two sintering procedures as hot-pressing and spark plasma sintering (SPS) were employed. The thermoelectric properties and mechanical strength were measured in all case. Thermoelectric properties for p-type (Bi0.25Sb0.75)2Te3 and n-type Bi2(Te0.2Se0.8)3 changed with sintering temperature in both sintering methods. Mechanical strength and relative density increase with sintering temperature in two sintering procedures. The results firmly suggest that both sintering procedures are promising to obtain high performance thermoelectric materials.


2017 ◽  
Vol 59 (11-12) ◽  
pp. 1033-1036 ◽  
Author(s):  
Sherzod Kurbanbekov ◽  
Mazhyn Skakov ◽  
Viktor Baklanov ◽  
Batyrzhan Karakozov

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3560
Author(s):  
Tomasz Skrzekut ◽  
Grzegorz Boczkal ◽  
Adam Zwoliński ◽  
Piotr Noga ◽  
Lucyna Jaworska ◽  
...  

Zr-2.5Cu and Zr-10Cu powder mixtures were consolidated in the extrusion process and using the spark plasma sintering technique. In these studies, material tests were carried out in the fields of phase composition, microstructure, hardness and tensile strength for Zr-Cu materials at room temperature (RT) and 400 °C. Fractography analysis of materials at room temperature and 400 °C was carried out. The research took into account the anisotropy of the materials obtained in the extrusion process. For the nonequilibrium SPS process, ZrCu2 and Cu10Zr7 intermetallic compounds formed in the material at sintering temperature. Extruded materials were composed mainly of α-Zr and ZrCu2. The presence of intermetallic compounds affected the reduction in the strength properties of the tested materials. The highest strength value of 205 MPa was obtained for the extruded Zr-2.5Cu, for which the samples were cut in the direction of extrusion. For materials with 10 wt.% copper, more participation of the intermetallic phase was formed, which lowered the mechanical properties of the obtained materials. In addition to brittle intermetallic phases, the materials were characterized by residual porosity, which also reduced the strength properties.


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.


2009 ◽  
Vol 24 (10) ◽  
pp. 3241-3245 ◽  
Author(s):  
Lianjun Wang ◽  
Wan Jiang ◽  
Lidong Chen ◽  
Zhijian Shen

A simple approach, order–disorder transition (ODT), has been developed to synthesize a novel glass using ZSM-5 as starting materials. In this process, the ZSM-5 powders were pressed uniaxially in a graphite die and rapidly sintered using spark plasma sintering (SPS). High-resolution transmission electron microscopic images revealed that a few crystalline zeolite fragments were still preserved locally inside the SPS consolidated sample. Vickers microhardness and fracture toughness of this as-prepared transparent glass sample at room temperature reaches 7.3 ± 0.2 GPa and 2.0 ± 0.3MPa·m1/2, respectively. It is very interesting that these novel bulk transparent glasses exhibit ultraviolet photoluminescence (PL) properties at about ∼360 nm.


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