Synthesis and characterization of precipitation hardened amorphous matrix composite by mechanical alloying and pulse plasma sintering of Al₆₅Cu₂₀Ti₁₅

Abstract

This study reports synthesis of Al₆₅Cu₂₀Ti₁₅ amorphous alloy by mechanical alloying and consolidation of the powder mass by pulsed plasma sintering. During sintering, several intermetallic phases precipitate from the amorphous matrix and cause a significant increase in nano-hardness and elastic modulus. Microstructure in as-milled and sintered conditions was characterized by X-ray diffraction, scanning/transmission electron microscopy and differential scanning calorimetric. Among various conditions of sintering, the composites pulse plasma, sintered at 500°C, show the high compression strength (1745 MPa) and high indentation fracture toughness (4.96 MPa m^1/2); although, the maximum density (3.73 Mg/in³), nano-hardness (14 GPa) and Young's modulus (208 GPa) in the present alloy have been obtained in the composites pulse plasma sintered at 600°C.

Keywords:

• amorphous alloy
• age hardening
• nanoscale precipitate
• mechanical property
• mechanical alloying
• pulse plasma sintering

Acknowledgements

The authors would like to thankfully acknowledge partial financial support provided for this research by CSIR, New Delhi (project no. 70(0048)/03-EMR-II) and DST, New Delhi (NSTI project no. SR/S5/NM-04/2005).