PSI - Issue 40

M.V. Fedorov et al. / Procedia Structural Integrity 40 (2022) 136–144

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Fedorov M. V. at al. / Structural Integrity Procedia 00 (2019) 000 – 000

1. Introduction. According to Loginov (1984), Panov et al. (2004), Levashov et al. (1984) and Shaskolskaya (1984) hardmetal materials have good physical and mechanical characteristics causing them to be widely used in various industries. Although carbide materials have high physical and mechanical characteristics, they are friable, resulting in low resistance to wear and abrasive shock loads. The brittleness of carbide materials during wear and abrasive shock loads results in spalling. At present, many scientific works investigate the issues of improving performance characteristics. The main ways of the improvement can be conditionally divided into surface and volumetric hardening. According to Shmatov et al. (2012), Samotugin (2016), Samotugin et al. (2014) and Ahman et al. (1985) there are main tools such as varying the dimensions of the components of hard-alloy powders (carbide and refractory phases), the development of new compositions with refractory additives, the introduction of new methods of preparation. In this work, studies of the processes occurring during solid-phase sintering of hard-alloy materials are carried out. The work aims to study the processes of solid-phase sintering of WC-Co (8%) powder at a temperature of 1450 ○ C. The following tasks were set to achieve this aim: X-ray spectral microanalysis and X-ray phase analysis of the initial WC-Co (8%), WC-WC, Co powders, thermal analysis of these powders from room temperature (28 ○ C) to 1450 ○ C, followed by X-ray phase analysis of the heated powders. 2. Statement of the problem and methods of solution. Hardmetal powder consists of refractory tungsten carbide and cobalt powders. Due to the different physical and chemical properties, it is necessary to consider them separately. Approximately 8 mg (precise band-and-hook hinge) of WC-Co (8%), WC-WC and Co powders were prepared. X-ray diffraction phase and micro-X-ray spectral analysis of the initial powders were carried out to determine their composition. Thermal analysis was carried out from room temperature to 1450 ○ C to study the processes that affect the properties of materials under the influence of temperature. The thermal analysis model was chosen close to the modes of traditional solid-phase sintering. It will make it possible to clarify the processes affecting the formation of the structure in hardmetal materials. Subsequently, X-ray phase analyses of the heated powders were carried out to establish the appearance of new phases. 3. Materials and methods. The object of research is a sample of tungsten carbide powder (WC-WC), a Cobalt powder (Co) and a mixture WC-Co(8%). The X-ray microanalysis is done using a scanning electron microscope JSM-6840LV (JEOL Ltd., Tokyo, Japan) with an Energy 350 Oxford Instruments energy dispersive spectrometer. Quantitative analysis and processing of the results were carried out using the XPP method of the Software INCA Energy software. The X-ray diffraction (XRD) phase analysis is done using a diffractometer PHASER D2 (Bruker, Ettlingen, Germany) for phase identification; the PDF-2 / Release 2011 RDB database was used to identify minerals. The thermal analysis was performed using the STA 449C Jupiter synchronous thermal analysis device from NETZSCH. Nomenclature WC tungsten carbide Co cobalt XRD X-ray diffraction PtRh platinum-rhodium