Near Full Density Nano Iron-Based Materials by Pulse Current Sintering

Constant current plus pulse current electrical sintering was introduced into the sintering of a ball-milled nanocrystalline Fe-2Cu-2Ni-1Mo-0.8C mixed powder. Effect of pulse current charging time on the properties of sintered products was studied. Constant electric current sintering was also used for comparison. A nanostructured iron-based material was obtained within 4 minutes of sintering. It has a density of 7.7 g/cm3 (relative density of 98.7 %) with an average grain size (iron-matrix) of 58 nm and carbide particle size of less than 100 nm, a hardness of HRC 64 and transverse rupture strength of 2004 MPa. When only pulsed electric current sintering was used with a sintering time of 5 min, a fine grained iron-base material with density of 7.74 g/cm3 (relative density of 99.2%), a hardness of HRC 65 and transverse rupture strength of 2045 MPa was obtained.

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Mechanical Properties of WC-Co Cemented Carbide Prepared via Vacuum Sintering

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.275-277.1917 ◽

2013 ◽

Vol 275-277 ◽

pp. 1917-1920

Author(s):

Bing Liang Liang ◽

Yun Long Ai ◽

Chang Hong Liu ◽

Nan Jiang

Keyword(s):

Mechanical Properties ◽

Phase Composition ◽

Relative Density ◽

Sintering Temperature ◽

Rupture Strength ◽

Cemented Carbide ◽

Vacuum Sintering ◽

Transverse Rupture Strength ◽

Temperature Range ◽

Peak Value

WC-Co cemented carbide specimens were prepared via vacuum sintering. The influences of composition and sintering temperature on phase composition, microstructure and mechanical properties of WC-Co cemented carbide were investigated. The results show that dense specimens were obtained in the sintering temperature range of 1280~1400°C and the relative density reached over 95%. Only WC and Co3W3C (-phase) were detected by XRD without any else phases, even though Co. With the ascended sintering temperature, hardness increased and the transverse rupture strength (TRS) ascended to peak value and then descended. WC-Co cemented carbide with excellent mechanical properties (HRA>90, TRS~700MPa and KIC>10MPa•m1/2) were obtained.

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Mechanical Behaviors of Metal-Bonded Diamond Abrasive Tools with Different Grit Sizes

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.359-360.73 ◽

2007 ◽

Vol 359-360 ◽

pp. 73-77 ◽

Cited By ~ 1

Author(s):

Yi Qing Yu ◽

Xiao Rui Tie ◽

Xi Peng Xu

Keyword(s):

Rare Earth ◽

Rupture Strength ◽

Grit Size ◽

Mechanical Behaviors ◽

Transverse Rupture Strength ◽

Close Relationship ◽

Abrasive Tools ◽

Iron Based ◽

Diamond Abrasive

The present study was undertaken to compare the hardness and transverse rupture strength (TRS) of metal-based tooling composites containing diamonds of different grit sizes. Two kinds of bond matrix, copper-based and iron-based, were applied in the fabrication of the composites. In the copper-based matrix, rare earth was used as an additive. Diamonds of three different grit sizes were incorporated into two bond matrix, thereby forming six kinds of diamond composites. SEM and EDS were used to analyze the fractured surfaces of the composites. It was found that the diamonds of medium grit size in the copper-based bond matrix led to the highest hardness and TRS. For the iron-based bond matrix, however, the hardness and TRS of the composites containing the coarsest diamonds were found to be the highest. In same bond matrix, a close relationship between TRS and hardness was established.

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Near Full Density Nano Iron-Based Materials by Pulse Current Sintering

Key Engineering Materials - Progresses in Fracture and Strength of Materials and Structures ◽

10.4028/0-87849-456-1.2143 ◽

2007 ◽

pp. 2143-2146

Author(s):

Yuan Yuan Li ◽

Yan Long ◽

Xiao Qiang Li ◽

Tung Wai Leo Ngai

Keyword(s):

Pulse Current ◽

Full Density ◽

Iron Based

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Pulse Electric Current Sintering of Iron-Base Powders Prepared by High Energy Milling

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.315-316.445 ◽

2006 ◽

Vol 315-316 ◽

pp. 445-449 ◽

Cited By ~ 2

Author(s):

Yuan Yuan Li ◽

Xiao Qiang Li ◽

Yan Long ◽

Ming Shao ◽

Wei Xia

Keyword(s):

Electric Current ◽

Milling Time ◽

Rupture Strength ◽

High Energy ◽

Sintered Alloy ◽

Transverse Rupture Strength ◽

Pulse Electric Current ◽

High Energy Milling ◽

Sintering Time ◽

Pulse Electric

Fe-2Cu-2Ni-1Mo-0.8C (wt. pct) alloys were successfully fabricated from elemental mixed powders by high energy milling and pulse electric current sintering, and the effects of milling time and sintering parameters on the densification degree, microstructure, mechanical properties and fracture characteristic of sintered material were investigated. Results showed that with increasing milling time, pulse electric current peak and sintering time, the density and transverse rupture strength of sintered alloy were improved. However, higher pulse electric current peak and/or longer sintering time were unfavorable to the density and strength of sintered alloy, because of generating overhigh sintering temperature. The density and transverse rupture strength of sintered alloy could reach 7.74 103 kg/m3 and 2231 MPa, respectively, and the corresponding fracture morphology was characterized as intergranular fracture.

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Fast Consolidation of Iron Powders by Pulse Electric Current Sintering

Materials Science Forum ◽

10.4028/www.scientific.net/msf.471-472.225 ◽

2004 ◽

Vol 471-472 ◽

pp. 225-229 ◽

Cited By ~ 1

Author(s):

Yuan Yuan Li ◽

Yan Long ◽

Xue Qin Li ◽

Wei Ping Chen ◽

Wei Xia

Keyword(s):

Electric Current ◽

Pulse Current ◽

Rupture Strength ◽

Optical Microscope ◽

Iron Powders ◽

X Ray ◽

Pulse Electric Current ◽

Pulse Peak ◽

Pulse Electric ◽

Short Heating

Iron powders were successfully consolidated by a Pulse Electric Current Sintering (PECS) process in a short heating duration of 6 min. Microstructure and chemical composition of the sintered samples were studied by an optical microscope, scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX). Experimental results showed that both the densification of powders and inter-diffusion between elements were accelerated by increasing of the pulse peak. No noticeable grain growth was observed in the sintered samples. When the peak of pulse current increased, the density and transverse rupture strength of the sintered samples were improved.

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The Development of WC-Based Composite Tools for Friction Stir Welding of High-Softening-Temperature Materials

Metals ◽

10.3390/met11020285 ◽

2021 ◽

Vol 11 (2) ◽

pp. 285 ◽

Cited By ~ 1

Author(s):

Mohamed M. Z. Ahmed ◽

Waheed S. Barakat ◽

Abdelkarim Y. A. Mohamed ◽

Naser A. Alsaleh ◽

Omayma A. Elkady

Keyword(s):

Fracture Toughness ◽

Friction Stir Welding ◽

Relative Density ◽

Rupture Strength ◽

Density Measurement ◽

Softening Temperature ◽

Temperature Deformation ◽

Transverse Rupture Strength ◽

Friction Stir ◽

High Softening Temperature

This work presents a detailed investigation for the effect of Y2O3 and Ni additions on the densification behavior, microstructural evolution and mechanical properties of a WC-Co-TaC-NbC composite. With the aim of obtaining WC-based composites with improved fracture toughness, to be used in severe conditions of high-temperature deformation, different concentrations of Y2O3 were incorporated with and without 5 wt% Ni addition. The consolidated composites were characterized using density measurement, XRD, SEM, hardness, fracture toughness, transverse rupture strength and compression testing. Fully dense composites were obtained through the applied consolidation regime of cold compaction and sintering at 1450 °C for 1.5 h under vacuum with a relative density up to 97%. The addition of 2.5 wt% Y2O3 to the base WC composite increased the relative density and then slightly decreased with the increase of the Y2O3 content. The addition of 5 wt% Ni to the base composites significantly increased the relative density to 97%. The XRD results indicated the existence of the Co3W3C η-phase after sintering, and the intensity of its peaks was reduced with the addition of 5 wt% Ni. The microstructure of the consolidated composites consisted of three phases: WC, Co3W3C and Y2O3. The area fraction of the Y2O3 phase increased as its weight fraction increased. In terms of the fracture toughness, the transverse-rupture strength (TRS) and the compressive strength were significantly improved by the addition of 5 wt% Ni with the 2.5 wt% Y2O3. Accordingly, this composition was used to manufacture the tools for the friction stir welding of the high-softening-temperature materials, which was successfully used for 25 plunges and about 500 cm of butt joints in nickel-based and carbon–steel alloys.

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