Karakterizacija mikrostrukture orodij izdelanih iz WC-Co

Kresnik, Žan (author), Naglič, Iztok (mentor)

Material WC-Co je sestavljen iz delcev volframovega karbida, obdanih z vezivom, ki ga predstavlja kovinski kobalt. Zaradi svoje visoke trdote in tlačne ter upogibne trdnosti, odlične toplotne prevodnosti, dobre odpornosti proti abraziji in trdnosti pri visokih temperaturah se pogosto uporablja za izdelavo rezalnih orodij. Namen diplomskega dela je bila karakterizacija in ugotavljanje morebitnih razlik med tremi vzorci žag, izdelanih iz materiala WC-Co. Pri karakterizaciji so bile uporabljene metode svetlobne mikroskopije, vrstične elektronske mikroskopije (SEM), energijsko disperzijske spektroskopije (EDS), rentgenske fazne analize (XRD) in kvantitativne analize mikrostrukture. Rezultati XRD analize so pokazali, da so v vseh vzorcih, poleg δ-WC, najverjetneje prisotne še naslednje faze: α-Co, oba tipa faze η (Co3W3C, Co6W6C), Cr3C2 in M7C3. S kvantitativno analizo mikrostrukture sem ugotovil, da je delež veziva v vzorcu 7A 3,72 %, v vzorcih 3A ter 4A pa 4,76 % in 4,66 %. Manjši delež veziva v vzorcu 7A potrjuje tudi XRD analiza. Povprečna površina zrn volframovega karbida v vzorcu 7A je 0,50 μm2, v vzorcih 3A ter 4A pa 0,68 μm2 in 0,73 μm2. Kljub manjši povprečni površini zrn pri vzorcu 7A pa sem našel posamezna zrna, večja od 2,45 μm2, kakršnih v ostalih dveh vzorcih nisem zasledil.

• Language: Slovenian
• Keywords: WC-Co, karakterizacija mikrostrukture, delež veziva, rentgenska fazna analiza, vrstična elektronska mikroskopija
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2018
• PID: 20.500.12556/RUL-103481
• COBISS.SI-ID: 1750111
• Publication date in RUL: 19.09.2018

KRESNIK, Žan, 2018, Karakterizacija mikrostrukture orodij izdelanih iz WC-Co [online]. Bachelor’s thesis. [Accessed 25 March 2025]. Retrieved from: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=eng&id=103481

Secondary language

• Language: English
• Title: Characterization of microstructure of WC-Co tools

Abstract

WC-Co material contains tungsten carbides surrounded by Co-based binder phase. These materials are commonly used for cutting tools, because of their excellent properties, such as: high hardness, high compression and flexural strength, great thermal conductivity, excellent abrasion resistance and high-temperature strength. The main purpose of this work was characterization and finding possible differences between three cutting tools, made of WC-Co. Characterization methods used in this work were: light microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and quantitative analysis of microstructure. According to the results of XRD analysis present phases in all three specimens (besides δ-WC) are: α-Co, both types of η phases (Co3W3C, Co6W6C), Cr3C2 and M7C3. Quantitative analysis of microstructure reveals that volume fraction of a binder phase in specimen 7A is 3.72 %, while in specimens 3A and 4A are 4.76 % and 4.66 %. Lower content of binder phase has also been proved by XRD analysis. It was found that the mean grain area of tungsten carbide grains in specimens 3A and 4A are 0.68 μm2 and 0,73 μm2, while in specimen 7A is 0,50 μm2. Despite smaller mean grain area, specimen 7A also contains grains larger than 2.45 μm2, which were not found in specimens 3A and 4A.

• Keywords: WC-Co, characterization of microstructure, binder content, X-ray diffraction, scanning electron microscopy