Effects of Compaction Velocity on the Sinterability of Al-Fe-Cr-Ti PM Alloy

Abstract

In this research, the effects of the compaction velocity on the sinterability of the Al–Fe–Cr–Ti powder metallurgy (PM) alloy by high velocity compaction were investigated. The Al–Fe–Cr–Ti alloy powder was compacted with different velocities by high velocity compaction and then sintered under a flow of high pure (99.999 wt%) nitrogen gas. Results indicated that both the sintered density and mechanical properties increased with increasing compaction velocity. By increasing the compaction velocity, the shrinkage of the sintered samples decreased. A maximum sintered density of 2.85 gcm−3 (relative density is 98%) was obtained when the compaction velocity was 9.4 ms−1. The radial and axial shrinkage were controlled to less than 1% at a compaction velocity of 9.4 ms−1. At a compaction velocity of 9.4 ms−1, sintered compacts with an ultimate tensile strength of 222 MPa and a yield strength of 160 MPa were achieved. The maximum elongation was observed to be 2.6%. The enhanced tensile properties of the Al–Fe–Cr–Ti alloy were mainly due to particle boundary strengthening.

Effects of Sintering Temperature on Densification, Microstructure and Mechanical Properties of Al-Based Alloy by High-Velocity Compaction

“…In this experiment, the theoretical density of Al-based alloy was 2.92 gcm −3 [20], and, with the increasing of sintering temperature, the sintered density gradually increased. The experimental results are consistent with the Arrhenius diffusion coefficient equation.…”

“…In this research, the compaction methods and raw materials of green were the same as the previous study. The main chemical compositions of the Al-based alloy powder were Al, Fe, Cr, Ti and chemical compositions (in wt%) were shown in [20].…”

“…The absence of quasicrystalline phase after sintering is due to the decomposition of the quasicrystalline phase at the high temperature [24]. The exothermic peaks of these phases decomposition are not observed on the DSC (Figure 2), because these phases only exist when the particle size is less than 25 µm [20]. The average particle size of the experimental powder is 25 µm, and the content of these phases is very small, which is almost invisible in the DSC experiment.…”

“…Moreover, an appropriate sintering temperature can contribute to the attainment of the economic sintering process since they can help to reduce the energy consumption of the sintering process [19]. The authors studied the effects of compaction velocity on sintered density and mechanical properties of Al-based alloy, and the results were published [20]. The previous study showed that the higher velocity of HVC contributed to the increasing of sintered density and mechanical properties of Al-based alloy.…”