Diffusional control of the near-surface microstructure in functional gradient hardmetals

✍ Scribed by W. Lengauer

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 446 KB
• Volume: 36
• Category: Article
• ISSN: 0933-5137
• DOI: 10.1002/mawe.200500906

✦ Synopsis

The efforts of the last several years of a research cooperation on diffusional near-surface microstructure modification of hardmetals are summarised. This modification was performed with a reactive gas supplied within the sintering cycle so that functional gradient hardmetals, FGHMs, were obtained, which show a graded distribution of phases. They were optimised for increased wear resistance in metal cutting operations. The thermochemical and diffusional basics of the preparation of two principally different FGHMs, one with an increased surface hardness and a decreased toughness (with 'regular gradient') and one with a decreased surface hardness but an increased toughness ('inverse gradient') are described in detail. Some of the developed grades were successfully tested and scaled up into industrial production. The FGHMs were found to outperform conventional hardmetals in certain machining tests (continuous turning as well as milling).