The Effect of Cr3C2 and TaC Additives on Microstructure, Hardness and Fracture Toughness of WC-6Co Tool Material Fabricated by Spark Plasma Sintering

Piotr Siwak,Michal Rogalewicz,Dariusz Garbiec

doi:10.1590/1980-5373-mr-2016-0889

Piotr Siwak, Michal Rogalewicz + Show 1 more

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https://doi.org/10.1590/1980-5373-mr-2016-0889

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Abstract

Spark plasma sintering has been used to successfully produce WC-6Co-xCr3C2, WC-6Co-xTaC (x = 0.2, 0.6, 1.0) and WC-6Co-xCr3C2-xTaC (x = 0.1, 0.3, 0.5) cemented carbides. The spark plasma sintered compacts were investigated by scanning electron microscopy, hardness tests and fracture toughness tests. The results were compared to an additives-free WC-6Co cemented carbide consolidated under the same process parameters and commercial ISO K10 inserts. By using Cr3C2 and TaC additives, it is possible to improve the hardness and fracture toughness of WC-Co cemented carbides. The best combination of hardness (1936 ± 15 HV30) and fracture toughness (10.38 ± 0.46 MPa∙m1/2) was obtained by the WC-6Co-1Cr3C2.

Highlights

Several authors’ studies[1,2,3] have concentrated on the relationship of the microstructure and properties of the cutting zone in industrial applications
It is well known that WC-Co cemented carbides are usually used as tool materials for machining, mining, cutting and drilling tools as well as wear resistance parts
Rumman et al.[19] explained that in WC-Co cemented carbides pores tend to decrease in size with an increasing compaction pressure

Summary

Introduction

Several authors’ studies[1,2,3] have concentrated on the relationship of the microstructure and properties of the cutting zone in industrial applications. It is well known that WC-Co cemented carbides are usually used as tool materials for machining, mining, cutting and drilling tools as well as wear resistance parts. Increasing the WC fraction can increase hardness and wear resistance, while fracture toughness can increase by increasing the Co content[9,10]. That is why WC-Co cemented carbides with 5-10 wt% Co are the most promising materials offering a very good balance of hardness and fracture toughness[10]. To increase the hardness and fracture toughness, some authors modified the structure of these materials with additives such as Cr3C211, TaC12-13, TiC13, VC12 and NbC14. Siwak and Garbiec in a previous study[15] proved that an addition of 2 wt% Cr3C2 and 2 wt% TaC to WC-5Co cemented carbides increased the hardness from 1512 to 2105 and 1725 HV30 respectively.

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