Solid solution synthesis of tantalum carbide-hafnium carbide by spark plasma sintering

2017 ◽  
Vol 100 (5) ◽  
pp. 1853-1862 ◽  
Author(s):  
Cheng Zhang ◽  
Ankur Gupta ◽  
Sudipta Seal ◽  
Benjamin Boesl ◽  
Arvind Agarwal
Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1268 ◽  
Author(s):  
Natalia Shkodich ◽  
Alexey Sedegov ◽  
Kirill Kuskov ◽  
Sergey Busurin ◽  
Yury Scheck ◽  
...  

For the first time, a powder of refractory body-centered cubic (bcc) HfTaTiNbZr-based high-entropy alloy (RHEA) was prepared by short-term (90 min) high-energy ball milling (HEBM) followed by spark plasma sintering (SPS) at 1300 °C for 10 min and the resultant bulk material was characterized by XRD and SEM/EDX. The material showed ultra-high Vickers hardness (10.7 GPa) and a density of 9.87 ± 0.18 g/cm³ (98.7%). Our alloy was found to consist of HfZrTiTaNb-based solid solution with bcc structure as a main phase, a hexagonal closest packed (hcp) Hf/Zr-based solid solution, and Me2Fe phases (Me = Hf, Zr) as minor admixtures. Principal elements of the HEA phase were uniformly distributed over the bulk of HfTaTiNbZr-based alloy. Similar alloys synthesized without milling or in the case of low-energy ball milling (LEBM, 10 h) consisted of a bcc HEA and a Hf/Zr-rich hcp solid solution; in this case, the Vickers hardness of such alloys was found to have a value of 6.4 GPa and 5.8 GPa, respectively.


2007 ◽  
Vol 534-536 ◽  
pp. 833-836 ◽  
Author(s):  
J.K. Lee ◽  
Taek Soo Kim ◽  
Ha Guk Jeong ◽  
Jung Chan Bae

The microstructure and mechanical properties of the Mg97Zn1Y2 alloy prepared by spark plasma sintering of gas atomized powders have been investigated. After consolidation, precipitates were observed to form in the α-Mg solid solution matrix of the Mg97Zn1Y2 alloy. These precipitates consisted of Mg12YZn and Mg24Y5 phases. The density of the consolidated bulk Mg-Zn-Y alloy was 1.86 g/cm3. The ultimate tensile strength and elongation were dependent on the consolidation temperature, which were in the ranges of 280 to 293 MPa and 8.5 to 20.8 %, respectively.


2010 ◽  
Vol 63 (6) ◽  
pp. 577-580 ◽  
Author(s):  
Evan Khaleghi ◽  
Yen-Shan Lin ◽  
Marc A. Meyers ◽  
Eugene A. Olevsky

2012 ◽  
Vol 1485 ◽  
pp. 9-20 ◽  
Author(s):  
Braeden M. Clark ◽  
James P. Kelly ◽  
Olivia A. Graeve

ABSTRACTThe sintering of tantalum carbide nanopowders by spark plasma sintering (SPS) is investigated. The washing procedure for the powders is modified from previous work to eliminate excess lithium in the powders that is left over from the synthesis process. The sintering behavior of the nanopowders is investigated by X-ray diffraction and scanning electron microscopy by studying specimens that were sintered to different temperatures. To improve the homogeneity of the microstructure of the specimens, milling procedures were implemented. Vaporization during sintering is observed, and the usefulness of carbon additions and systematic decreases in temperature to curb this behavior was explored. Future experiments to achieve full density and to maintain a nanostructure of the specimens include sintering with higher pressures, lower temperatures, and longer dwell times. Additives for maintaining a nanostructure and developing suitable high-temperature properties are also discussed.


2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
Xiaoyong Ren ◽  
Zhijian Peng ◽  
Zhiqiang Fu ◽  
Chengbiao Wang

Ultrafine tungsten carbide-nickel (WC-Ni) cemented carbides with varied fractions of silicon carbide (SiC) nanowhisker (0–3.75 wt.%) were fabricated by spark plasma sintering at 1350°C under a uniaxial pressure of 50 MPa with the assistance of vanadium carbide (VC) and tantalum carbide (TaC) as WC grain growth inhibitors. The effects of SiC nanowhisker on the microstructure and mechanical properties of the as-prepared WC-Ni cemented carbides were investigated. X-ray diffraction analysis revealed that during spark plasma sintering (SPS) Ni may react with the applied SiC nanowhisker, forming Ni2Si and graphite. Scanning electron microscopy examination indicated that, with the addition of SiC nanowhisker, the average WC grain size decreased from 400 to 350 nm. However, with the additional fractions of SiC nanowhisker, more and more Si-rich aggregates appeared. With the increase in the added fraction of SiC nanowhisker, the Vickers hardness of the samples initially increased and then decreased, reaching its maximum of about 24.9 GPa when 0.75 wt.% SiC nanowhisker was added. However, the flexural strength of the sample gradually decreased with increasing addition fraction of SiC nanowhisker.


Sign in / Sign up

Export Citation Format

Share Document