Mechanical Property of Porous Titanium Produced by Spark Plasma Sintering

2008 ◽  
Vol 385-387 ◽  
pp. 637-640 ◽  
Author(s):  
Yuki Sakamoto ◽  
Shigeaki Moriyama ◽  
Masahiro Endo ◽  
Yuji Kawakami

Titanium has widely been used as a biomaterial because of its excellent corrosion resistance and biocompatibility. However, problems with respect to biological reaction and fitness of elastic modulus for human bone or tooth have yet to be solved. Porous titanium is expected to be a promising material to solve these problems. The aim of this study is to clarify the effect of the porous structure of this material on the biomechanical compatibility. The spherical pure titanium powder, with an average particle size of 100 µm, was sintered by spark plasma sintering. The sintered porous titanium compacts had a porosity of 33 %. The specimens were machined from the sintered compacts for the evaluation of the mechanical properties. The elastic modulus indicated a value close to human bone, while the tensile and compressive strengths showed lower values than those of human bone.

2006 ◽  
Vol 317-318 ◽  
pp. 917-920
Author(s):  
Jae Kwang Kim ◽  
Kyung Hun Kim ◽  
Yong Ho Choa ◽  
Jong Won Yoon ◽  
Kwang Bo Shim

Dense 8mol% yttria-stabilized zirconia (8YSZ) consisting of submicrometer-sized grains was prepared using spark plasma sintering (SPS) along with Al2O3 additives. The starting powder with average particle size of 50nm was densified to 98% of the relative density with short sintering time (5min) at 1200 while preserving a submicrometer grain size. The fracture toughness and bending strength showed maximum values of 2.54MPam1/2 and 380MPa at 2vol% alumina-added 8YSZ, due mainly to the higher relative density and small grain size. The electrical conductivity of 2vol% alumina-added 8YSZ was 0.0278 S/cm at 700 in airThus, alumina additions in 8YSZ using the SPS method are an effective process to improve the mechanical strength and electrical conductivity.


2005 ◽  
Vol 287 ◽  
pp. 160-165 ◽  
Author(s):  
Ji Soon Kim ◽  
Young Do Kim ◽  
Choong Hyo Lee ◽  
Pyuck Pa Choi ◽  
Young Soon Kwon

The effect of milling on the densification behavior of MoSi2 powder during spark-plasma sintering (SPS) was investigated. MoSi2 starting powder with an average particle size of 10 µm was milled to reduce particle sizes to less than 1 µm. Sintering was performed in a SPS facility, varying the sintering temperature from 1200°C to 1500°C. Changes in relative density and the densification rate were measured as a function of temperature. Additionally, the microstructure of sintered compacts was analyzed by means of SEM and EPMA. The sintered density was lower for ballmilled powder compacts (having 94-95% relative density) than for as-received ones (having 94- 98% relative density) despite a higher densification rate of the former in the early and middle stages of sintering. These apparently contradictory results can be explained by a pick-up of oxygen (from 0.3 to 1.8 wt. % O) during the milling process, leading to the formation of silicon oxide and its decomposition into a gas phase at temperatures above 1200°C.


Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2443 ◽  
Author(s):  
Zhenhua Wang ◽  
Jiheng Jia ◽  
Boxiang Wang ◽  
Yulin Wang

Ultrafine grained WC-12Co-0.2VC (named UYG12V) cemented carbides were prepared via the two-step spark plasma sintering (SPS) in this study. First, the effects of the sintering temperature on the relative density and WC grain size of UYG12V cemented carbides were studied. The results show that regular WC grains form when sintered at 1300 °C. The sintered body begins to rapidly densify and WC grains grow slowly when sintered at 1200 °C. Thus, the first-step (T1) and the second-step (T2) temperatures in the two-step SPS of UYG12V are 1300 °C and 1200 °C, respectively. The effect of the holding time during the first and second steps on the mechanical properties was also studied. The results show that the UYG12V cemented carbide sintered at 1300 °C for 3 min and then at 1200 °C for 5 min has the best comprehensive mechanical properties, exhibiting the average particle size, Vickers hardness, fracture toughness, relative density, and bending strength of 271 nm, 18.06 GPa, 12.25 MPa m1/2, 99.49%, and 1960 MPa, respectively.


Metals ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 82
Author(s):  
Shifeng Liu ◽  
Guangxi Zhang ◽  
Mingjun Shi ◽  
Xin Yang ◽  
An Li

Porous titanium samples with a porosity of 1.34~15.54% were prepared by a spark plasma sintering (SPS) process at sintering temperatures of 800 °C, 850 °C and 900 °C, and a sintering pressure of 10 MPa. The microstructures and fracture morphology of the samples were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The compressive strength and elastic modulus were likewise measured. The results showed that no new phase occurred after the samples were sintered, and the main phases were α phase of hcp structure. The porosity of the samples decreased significantly with the increase of sintering temperature. At 800 °C, the sample phase was dominated by equiaxed α. There were more irregular coarse pores in the samples. At 850 °C, the microstructure was mainly zigzag α, and the pores were finely and relatively uniform in distribution. At 900 °C, the sample’s structure transformed into a dense sheet-like α. The sample’s densities increased and the pores disappeared. The room temperature compression test showed that the porous titanium sintered by SPS had excellent compressive strength. The yield strength, compressive strength, compressive strain and elastic modulus were 81.85~122.36 MPa, 161.65~498.86 MPa, 36.75~59.97% and 2.79~4.22 GPa, respectively.


Author(s):  
N. A. Kochetov ◽  
A. S. Rogachev ◽  
A. S. Shchukin ◽  
S. G. Vadchenko ◽  
I. D. Kovalev

This paper presents the results of studying the mechanical alloying (MA) effect on the surface morphology, microstructure and atomic-crystal structure of multicomponent Fe–Cr–Co–Ni–Mn powder mixture particles. The following materials were used as initial components: radio-engineering carbonyl iron powder (R-10 with an average particle size d = 3,5 μm), nickel powder (NPE-1, d = 150 μm), cobalt powder (PK-1u, d <71 μm), chromium powder (PH-1М, d <125 μm) and manganese powder (MR0, d <400 μm) were used. MA of the prepared mixture was carried out in the AGO-2 water-cooled mechanical activator using 9 mm steel balls with an acceleration of 90 g in air. Alloying time varied between 5 and 90 minutes. The ratio of ball mass to the mass of the mixture was 20 : 1. X-ray patterns of the initial and alloyed mixtures and the sample obtained by sintering were made on the DRON 3M diffractometer on FeKα radiation in the range of angles 2θ = 30°÷100°. The particle microstructure of the mixtures and compact sample section after sintering was studied by scanning electron microscopy. It is found that no peaks of the initial components are present on the X-ray pattern of the mixture after 90 minutes of mechanical activation, but there are peaks corresponding to the γ-Fe-based solid solution phase having a face-centered crystal lattice with an amorphous phase content increased by 20 %. A compact single-phase material was obtained by spark plasma sintering at 800 °С for 10 minutes from the mixture after 90-minute alloying. Material density was 7,49 kg/cm3, specific electrical resistivity was 0,94÷0,96·10–6 ·m, microhardness was 306÷328 kg/mm2, and the phase was distributed uniformly throughout the volume.


2020 ◽  
Vol 20 (7) ◽  
pp. 4521-4524
Author(s):  
Ju-Yeon Han ◽  
Hyunji Kang ◽  
Young-Keun Jeong ◽  
Sung-Tag Oh

The synthesis and consolidation of nano-sized W powders are attempted with the combination process of hydrogen reduction of ball-milled WO3 powder and spark plasma sintering. The reduction behavior of WO3 is analyzed by temperature-programmed reduction. The reaction peaks for reduction of WO3 are observed in the temperature range of 590–782 °C. XRD and TEM analysis reveals that oxide powder is changed to metallic W with an average particle size of 100 nm by hydrogen reduction at 900 °C for 1 h. The densified specimen by spark plasma sintering at 1700 °C under an applied pressure of 50 MPa using nano-sized W powder shows increased relative density compared with that using micron-sized W powder. The results suggested that the W bulk with increased relative density fine microstructure can be fabricated by spark plasma sintering of hydrogen-reduced WO3 powder, more effectively.


2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
M. Suárez ◽  
A. Fernández ◽  
J. L. Menéndez ◽  
R. Torrecillas

Lyophilized YAG gel, synthesized by the coprecipitation technique, has been sintered to transparency by spark plasma sintering method at1500∘C. Whereas conventionally dried gels show large agglomerates, over 1 μm, powders from lyophilized gels show no agglomeration with an average particle size below 100 nm. The absence of agglomerates affects on the optical properties of the sintered materials: conventionally dried powders are opaque after sintering, whereas 0.8 mm thick transparent YAG materials with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range have been obtained for the lyophilized gels.


Author(s):  
Chander Prakash ◽  
Sunpreet Singh ◽  
Ahmad Majdi Abdul-Rani ◽  
M. S. Uddin ◽  
B. S. Pabla ◽  
...  

In this chapter, low elastic modulus porous Mg-Zn-Mn-(Si, HA) alloy was fabricated by mechanical alloying and spark plasma sintering technique. The microstructure, topography, elemental, and chemical composition of the as-sintered bio-composite were characterized by optical microscope, FE-SEM, EDS, and XRD technique. The mechanical properties such as hardness and elastic modulus were determined by nanoindentation technique. The as-sintered bio-composites show low ductility due to the presence of Si, Ca, and Zn elements. The presence of Mg matrix was observed as primary grain and the presence of coarse Mg2Si, Zn, and CaMg as a secondary grain boundary. EDS spectrum and XRD pattern confirms the formation of intermetallic biocompatible phases in the sintered compact, which is beneficial to form apatite and improved the bioactivity of the alloy for osseointegration. The lowest elastic modulus of 28 GPa was measured. Moreover, the as-sintered bio-composites has high corrosion resistance and corrosion rate of the Mg was decreased by the addition of HA and Si element.


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