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Self-consolidation mechanism of nanostructured Ti5Si3 compact induced by electrical discharge.

Lee WH, Cheon YW, Jo YH, Seong JG, Jo YJ, Kim YH, Noh MS, Jeong HG, Van Tyne CJ, Chang SY - ScientificWorldJournal (2015)

Bottom Line: A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge.Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact.Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea.

ABSTRACT
Electrical discharge using a capacitance of 450 μF at 7.0 and 8.0 kJ input energies was applied to mechanical alloyed Ti5Si3 powder without applying any external pressure. A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge. During an electrical discharge, the heat generated is the required parameter possibly to melt the Ti5Si3 particles and the pinch force can pressurize the melted powder without allowing the formation of pores. Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact. Three stepped processes during an electrical discharge for the formation of nanostructured Ti5Si3 compact are proposed: (a) a physical breakdown of the surface oxide of Ti5Si3 powder particles, (b) melting and condensation of Ti5Si3 powder by the heat and pinch pressure, respectively, and (c) rapid cooling for the preservation of nanostructure. Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

No MeSH data available.


Related in: MedlinePlus

A schematic diagram of the experimental setup for the electrical discharge consolidation (EDC) technique.
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fig1: A schematic diagram of the experimental setup for the electrical discharge consolidation (EDC) technique.

Mentions: 0.34 grams of MAed powder was vibrated into a quartz tube with an inner diameter of 4.0 mm that had a tungsten electrode at the bottom and top. The discharging chamber was evacuated to 2 × 10−2 torr. A capacitor bank of 450 μF was charged with two different electrical input energies (7.0 and 8.0 kJ). The charged capacitor bank instantaneously discharged through the MAed powder column without applying any pressure by on/off high vacuum switch which closes the discharge circuit. The voltage and current that the powder column experiences when the circuit is closed were simultaneously picked up by a high voltage probe and a high current probe, respectively. Outputs from these probes are fed into a high speed oscilloscope that stores them as a function of discharge time. The overall process is referred to as electrical discharge consolidation (EDC). A schematic of the EDC apparatus is shown in Figure 1.


Self-consolidation mechanism of nanostructured Ti5Si3 compact induced by electrical discharge.

Lee WH, Cheon YW, Jo YH, Seong JG, Jo YJ, Kim YH, Noh MS, Jeong HG, Van Tyne CJ, Chang SY - ScientificWorldJournal (2015)

A schematic diagram of the experimental setup for the electrical discharge consolidation (EDC) technique.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4389978&req=5

fig1: A schematic diagram of the experimental setup for the electrical discharge consolidation (EDC) technique.
Mentions: 0.34 grams of MAed powder was vibrated into a quartz tube with an inner diameter of 4.0 mm that had a tungsten electrode at the bottom and top. The discharging chamber was evacuated to 2 × 10−2 torr. A capacitor bank of 450 μF was charged with two different electrical input energies (7.0 and 8.0 kJ). The charged capacitor bank instantaneously discharged through the MAed powder column without applying any pressure by on/off high vacuum switch which closes the discharge circuit. The voltage and current that the powder column experiences when the circuit is closed were simultaneously picked up by a high voltage probe and a high current probe, respectively. Outputs from these probes are fed into a high speed oscilloscope that stores them as a function of discharge time. The overall process is referred to as electrical discharge consolidation (EDC). A schematic of the EDC apparatus is shown in Figure 1.

Bottom Line: A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge.Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact.Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747, Republic of Korea.

ABSTRACT
Electrical discharge using a capacitance of 450 μF at 7.0 and 8.0 kJ input energies was applied to mechanical alloyed Ti5Si3 powder without applying any external pressure. A solid bulk of nanostructured Ti5Si3 with no compositional deviation was obtained in times as short as 159 μsec by the discharge. During an electrical discharge, the heat generated is the required parameter possibly to melt the Ti5Si3 particles and the pinch force can pressurize the melted powder without allowing the formation of pores. Followed rapid cooling preserved the nanostructure of consolidated Ti5Si3 compact. Three stepped processes during an electrical discharge for the formation of nanostructured Ti5Si3 compact are proposed: (a) a physical breakdown of the surface oxide of Ti5Si3 powder particles, (b) melting and condensation of Ti5Si3 powder by the heat and pinch pressure, respectively, and (c) rapid cooling for the preservation of nanostructure. Complete conversion yielding a single phase Ti5Si3 is primarily dominated by the solid-liquid mechanism.

No MeSH data available.


Related in: MedlinePlus