Microstructure and Phase Transformation Behaviour of Co–Ni–Al Alloy by Spark Plasma Sintering

Comparative study of conventionally sintered Co-Ni-Al alloy with spark plasma sintered alloy

“…Z. H. Liu et al [15] also examined two different super lattice peaks in addition to the fundamental peaks, which represent the cubic β structure. The β phase structure of the as-sintered Co-Ni-Al alloy is in uniform order, proving the austenite phase with the lattice parameter a = 11.39, which is similar to the SPS alloy [12]. The combination of β phase and γ phase of the as-sintered alloy is confirmed by their peak which shows that they have high ductility.…”

“…The morphological images show mild presence of oxidation during the process of sintering at 673 K [17]. By comparing the SEM image of the SPS alloy [12] with the assintered alloy, we find the presence of pores with agglomeration of particles, which is not large enough to prevent the grain growth. Also, due to the high densification rate of the as-sintered alloy, the grain growth might have merged the pores together to become a larger one.…”

“…In the as-sintered alloy, along with the high intensity plane at (110), few more peaks are observed along γ(111), β(200), γ(200), γ(220) which indicate that the alloy is in martensite phase with cubic structure. From the peaks, in the SPS alloy [12] and in the assintered alloy, it has been observed that there is a minor shift of 0.2 degree in the lower angle side, which might have been caused by the internal stress present in the alloy. Z. H. Liu et al [15] also examined two different super lattice peaks in addition to the fundamental peaks, which represent the cubic β structure.…”

“…The highly compacted alloy, having green density of 4.479, sintered at 673 K has been studied further and they are compared with the SPS alloy. For the preparation of SPS alloy, the stoichiometric Co 38 Ni 35 Al 27 alloy powders were sintered to 20mm disks by SPS system at a pressure of 50 MPa with a heating rate of 150 °C/min to peak temperatures of 1000 °C with a dwell time of 5 minutes [12]. The phase analysis and the crystalline nature of the alloy were studied by X-ray diffractometer technique.…”

“…In the paper [12], the spark plasma sintered Co-Ni-Al alloy was studied for its microstructure and phase transformation behaviour. The present study investigates the structural, morphological studies, mechanical and magnetic properties of the conventionally sintered alloys and the SPS sintered alloys.…”