ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The purpose of this paper is the evaluation of the use of a low power CO2 laser beam(50W) to promote the thermal treatment of AISI M2 high-speed steels and evaluate the tribologicalproperties of the graphite coating that takes place on the steel surface after laser irradiation. In orderto minimize the steel surface reflection at approximately 90% of the incident radiation wavelength(10.5 μm), an incident radiation absorber layer was applied to the steel surface sample. This coatingaims to absorber the incident heat and transfer part of heat to the steel surface. As results the surfacepresented high hardness and a thin coating of graphite on the surface. The micro-structural changes,occurred on the steels surface, resulting from heat transfer from the absorbing layer, were evaluatedthrough optical microscopy (MO), scanning electron microscopy (MEV), micro-hardness essays(MH), X-ray analysis (XRD), Raman spectroscopy and tribological testers on the graphite coating.MO analysis showed on the transversal section of the heated affected zone a brighter layer than thesample’s core, 30 micrometers thickness, in the surface sample a black coat 10 micrometersthickness. By MH analysis this brighter layer presented hardness approximately 30% superior thanthe regions without treatment, and by Raman spectroscopy it was evaluated the graphite coating.The XRD analysis on the surface sample reveals an increasing of the martensite and iron-carbidephase. The experimental results of pin-on-disk tests on the graphite coatings reveal a reducedcoefficient friction as compared to the original surface
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.591-593.62.pdf
