Wyniki wyszukiwania - BazTech

1

Properties of TiC-Mo2C-WC-Ni Cermets by a High-Energy Ball Milling/Spark Plasma Sintering

Lee Jeong-Han, Park Jae-Cheol, Park Hyun-Kuk

Archives of Metallurgy and Materials

|

2023

|

Vol. 68, iss. 1

127--130

EN

A TiC-Mo2C-WC-Ni alloy cermet was fabricated by high-energy ball milling (HEBM) and consolidation through spark plasma sintering. The TiC-based powders were synthesized with different milling times (6, 12, 24, and 48 h) and subsequently consolidated by rapid sintering at 1300°C and a load of 60 MPa. An increase in the HEBM time led to improved sinterability as there was a sufficient driving force between the particles during densification. Core-rim structures such as (Ti, W)C and (Ti, Mo)C (rim) were formed by Ostwald ripening while inhibiting the coarsening of the TiC (core) grains. The TiC grains became refined (2.57 to 0.47 µm), with evenly distributed rims. This led to improved fracture toughness (11.1 to 14.8 MPa·m1/2) owing to crack deflection, and the crack propagation resistance was enhanced by mitigating intergranular fractures around the TiC core.

2

Effects of Transition Metal Carbides on Microstructure and Mechanical Properties of Ultrafine Tungsten Carbide Via Spark Plasma Sintering

Lee Jeong-Han, Oh Ik-Hyun, Park Hyun-Kuk

Archives of Metallurgy and Materials

|

2021

|

Vol. 66, iss. 4

1029--1032

EN

WC-Co cemented carbides were consolidated using spark plasma sintering in the temperature 1400°C with transition metal carbides addition. The densification depended on exponentially as a function of sintering exponent. Moreover, the secondary (M, W)Cx phases were formed at the grain boundaries of WC basal facet. Corresponded, to increase the basal facets lead to the plastic deformation and oriented grain growth. A higher hardness was correlated with their grain size and lattice strain. We suggest that this is due to the formation energy of (M, W)Cx attributed to inhibit the grain growth and separates the WC/Co interface.

3

Consolidation and Oxidation of Ultra Fine WC-Co-HfB2 Hard Materials by Spark Plasma Sintering

Park Hyun-Kuk, Oh Ik-Hyun, Kim Ju-Hun, Hong Sung-Kil, Lee Jeong-Han

Archives of Metallurgy and Materials

|

2021

|

Vol. 66, iss. 4

997--1000

EN

In this study, a novel composite was fabricated by adding the Hafnium diboride (HfB2) to conventional WC-Co cemented carbides to enhance the high-temperature properties while retaining the intrinsic high hardness. Using spark plasma sintering, high density (up to 99.4%) WC-6Co-(1, 2.5, 4, and 5.5 wt. %) HfB2 composites were consolidated at 1300°C (100°C/min) under 60 MPa pressure. The microstructural evolution, oxidation layer, and phase constitution of WC-Co-HfB2 were investigated in the distribution of WC grain and solid solution phases by X-ray diffraction and FE-SEM. The WC-Co-HfB2 composite exhibited improved mechanical properties (approximately 2,180.7 kg/mm2) than those of conventional WC-Co cemented carbides. The high strength of the fabricated composites was caused by the fine-grade HfB2 precipitate and the solid solution, which enabled the tailoring of mechanical properties.