Experimental Investigation by Cryogenic Treatment of Aluminium 6063 and 8011 and NiCoW Coating to Improve Hardness and Wear (TECHNICAL NOTE)

The aim of this paper is to focus on the effect of cryogenic treatment on the microstructure, mechanical and wear properties of Al 6061 and Al 8011.  The first objective was to understand the degree to which hardness of these aluminium grades have been enhanced by giving  cryogenic on the specimens. The second objective is to check the wear resistance property of these two aluminium specimens if coated with NiCoW and then treating it cryogenically. To conduct hardness tests specimens were fabricated from aluminium plates from both these grades and cryogenically treated. To conduct wear test Aluminium was coated with NiCoW on both the grades of aluminium and the experimental investigation has been carried out on aluminium alloys with cryogenic coolants. The hardness and wear removal rate were studied for both the specimens. The cryogenic coolant has enhanced the hardenability of aluminium alloys resulting in increased hardness of nearly 15%. The cryogenic coolant has increased the wear resistance properties of aluminium coated with NiCoW by nearly 25% when compared to wear of aluminium not treated with the coating materials.  The cryogenic treatment was carried out under three different timings of 8 hrs, 24 hrs and 48 hrs for three different rpm’s 300, 600, 800 under varying loads. The paper also studies the micro structural changes under these varying conditions.