US 12,109,616 B2
Method and system for improving the surface fracture toughness of brittle materials, and a cutting tool produced by such method
Claudia Polese, Johannesburg (ZA); Daniel Glaser, Johannesburg (ZA); Lesley A. Cornish, Johannesburg (ZA); and Rodney M. Genga, Johannesburg (ZA)
Assigned to University of the Witwatersrand, Johannesburg (ZA); and CSIR, Pretoria (ZA)
Appl. No. 16/617,335
Filed by University of the Witwatersrand, Johannesburg, Johannesburg (ZA); and CSIR, Pretoria (ZA)
PCT Filed May 28, 2018, PCT No. PCT/IB2018/053772
§ 371(c)(1), (2) Date Nov. 26, 2019,
PCT Pub. No. WO2018/215996, PCT Pub. Date Nov. 29, 2018.
Claims priority of application No. 2018981 (NL), filed on May 26, 2017.
Prior Publication US 2020/0102634 A1, Apr. 2, 2020
Int. Cl. B22F 3/105 (2006.01); B22F 3/24 (2006.01); B22F 5/00 (2006.01); C21D 10/00 (2006.01); C22C 29/06 (2006.01); C22C 29/08 (2006.01); C22F 3/00 (2006.01)
CPC B22F 3/105 (2013.01) [B22F 3/24 (2013.01); B22F 5/00 (2013.01); C21D 10/005 (2013.01); C22C 29/067 (2013.01); C22C 29/08 (2013.01); C22F 3/00 (2013.01); B22F 2005/001 (2013.01); B22F 2301/15 (2013.01); B22F 2302/10 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method of improving the wear resistance of a cemented carbide, the method including:
selecting a cemented carbide which has a fracture toughness value between about 6 and about 15 MPa·m1/2;
applying a sacrificial thermo-protective overlay to the cemented carbide; and
creating a toughened surface layer by inducing residual compressive stresses in a substrate of the cemented carbide using laser shock peening with a laser source capable of delivering between about 300 mJ to about 600 mJ to the cemented carbide at a pulse duration of between about 7 ns and about 10 ns (FWHM), a spot size between about 0.7 and about 1.2 mm, a power intensity of between about 7.5 and about 8.5 GW/cm2, and an overlap of between 0 and 90%, wherein the laser shock peening increases the fracture resistance to fatigue and stress corrosion cracking in the toughened surface layer as a result of an increase in fracture toughness while maintaining microhardness.