The Structure and Mechanical Properties of High-Strength Bulk Ultrafine-Grained Cobalt Prepared Using High-Energy Ball Milling in Combination with Spark Plasma Sintering

Abstract

In this study, bulk ultrafine-grained and micro-crystalline cobalt was prepared using a combination of high-energy ball milling and subsequent spark plasma sintering. The average grain sizes of the ultrafine-grained and micro-crystalline materials were 200 nm and 1 μm, respectively. Mechanical properties such as the compressive yield strength, the ultimate compressive strength, the maximum compressive deformation and the Vickers hardness were studied and compared with those of a coarse-grained as-cast cobalt reference sample. The bulk ultrafine-grained sample showed an ultra-high compressive yield strength that was greater than 1 GPa, which is discussed with respect to the preparation technique and a structural investigation.

Compression strength of tungsten carbide–cobalt hard metals

“…in compression between 10% and 31%. 33 Further compounding this variation is the level of Co contiguity in each material. Dislocations will be easier to move within a large volume of Co compared to a thin film that typically exists between multiple WC grains in a material that has high Co contiguity.…”

Thermoelectric Properties and Stability of Nanocomposites Type I Clathrate Ba‐Cu‐Si with SiC

“…[5,11] A simple and very economic approach is to produce nanopowders by ball milling, then to compact them to bulks by hot pressing (HP), spark plasma sintering (SPS) etc. [5,11,29,30] Nanostructured materials produced by this method indeed show obviously improved TE performance. [5,11] However, grain growth in such nanostructured materials is unavoidable, since nanostructures are metastable because of the high surface energy stored in grain boundaries.…”

“…Bulk nanostructured materials in large quantities can be produced easily and have been widely accepted in TE material research , . A simple and very economic approach is to produce nanopowders by ball milling, then to compact them to bulks by hot pressing (HP), spark plasma sintering (SPS) etc , , , . Nanostructured materials produced by this method indeed show obviously improved TE performance , .…”

Microstructure and Mechanical Properties of Ti-25Nb-4Ta-8Sn Alloy Prepared by Spark Plasma Sintering

“…Owing to the high sintering speed and pressure, materials with almost theoretical density and fine-grained structure can be prepared. Through this process, significantly better mechanical properties of the material can be achieved [ 27 , 28 ]. In this study, we used the spark plasma sintering technique to prepare a quaternary Ti-25Nb-4Ta-8Sn alloy.…”