Effect of sintering temperature on phase evolution of Al86Ni6Y4.5Co2La1.5 bulk amorphous composites synthesized via mechanical alloying and spark plasma sintering

Publication date: Available online 14 February 2019Source: Progress in Natural Science: Materials InternationalAuthor(s): Ashutosh Sahu, Ram Sajeevan Maurya, Tapas LahaAbstractAl86Ni6Y4.5Co2La1.5 amorphous powders were synthesized by mechanical alloying for 200 h. Subsequent consolidation was performed via spark plasma sintering in the temperature range of 250 °C to 500 °C at the pressure of 500 MPa. The role of viscous flow on densification was investigated by studying the viscosity change of the amorphous phase at different consolidation temperatures. The decrease in viscosity at higher sintering temperatures resulted in better particle bonding and densification of consolidated samples. The formation of only FCC Al was observed in the consolidated samples at sintering temperatures ≤ 300 °C and the intermetallic phases formed at temperatures ≥ 400 °C. The mechanical properties of the bulk samples were measured by Vickers microhardness and nanoindentation tests. The testing results showed that the average values of microhardness, nanohardness and elastic modulus of the sample consolidated at 500 °C were 3.06 ± 0.14 GPa, 4.85 ± 1.14 GPa and 89.53 ± 9.25 GPa, respectively. The increase in hardness and elastic modulus of the higher temperature consolidated samples is attributed to the improvement in particle bonding, densification and distribution of various hard intermetallic phases in the amorphous matrix.Graphical abstract
Source: Progress in Natural Science: Materials International - Category: Materials Science Source Type: research