Investigation on in-situ formed Al3V-Al-VC nano composite through conventional, microwave and spark plasma sintering

Abstract

In the present study, the effect of heating methods has been studied on the microstructure and mechanical properties of in-situ formed Al₃V-Al-VC nano-composite. 5 and 15 wt % of VC were added to Al matrix and conventional and microwave sintering processes were performed at 600 °C. While spark plasma sintering process was done at 450 °C with initial and final pressure of 10 and 30 MPa, respectively. The XRD results revealed the formation of Al₃V intermetallic compound in microwave sintered sample, while in both spark plasma sintered and conventionally prepared specimens, the only crystalline phases were Al and VC. Microstructure studies, demonstrated a uniform distribution of 5wt% VC reinforcement in Al matrix but the 15wt%VC addition led to form agglomerates in all prepared samples. The highest bending strength (275 ± 13 MPa) and hardness (260 ± 13 Vickers) were obtained in the spark plasma sintered sample with 15wt% of VC content.

Keywords: Aerospace engineering; Materials science; Nanotechnology.

Fig. 1

Displacement, temperature and displacement rate vs. sintering time of SPSed samples: a) Al-5wt%VC and b) Al-15wt%VC.

Fig. 2

XRD patterns of Al-15wt%VC composites prepared by spark plasma, microwave and conventional sintering.

Fig. 3

Backscattered FESEM images of Conventionally (a and b), MW (c and d) and SPS (e and f) sintered samples: a,c and e) Al-5wt%VC and b, d and f) Al-15wt%VC nano composites.

Fig. 4

Backscattered FESEM image of the MW Al-5wt%VC sintered sample at 600 °C (a), overlapping of Al, C and V on original picture as background, overlay of Al, C and V (C) and corresponding EDS elemental mapping of Al (d), C (e) and V(f).

Fig. 5

Backscattered FESEM images of the MW Al-15wt%VC sintered sample at 600 °C (a and b), corresponding EDS elemental mapping of C (c), Al (d) and V(e) and overlapping of C (f), V (g) and Al (h) on original picture as background.

Fig. 6

Schematic principles of different heating methods influence on sintering mechanism.

Fig. 7

Density changes vs. reinforcement content of the samples prepared with different heating methods.

Fig. 8

Load-extension curves during the bending strength test for the SPS, microwave and conventionally-sintered Al-5wt%VC (a) and Al-15wt%VC (b) composites.