Characterization and single track analysis of a metal-ceramic composite laser cladding over Ti6Al4V alloy

Abstract

The present experimental investigation is dealt with the formation of composite cladding on Ti6Al4V alloy using laser melting and deposition (LMD) technique. The reinforcement consisting of ilmenite (Fe-TiO3), CeO2, La2O3, cubic boron nitride (cBN) and Ti6Al4V in different compositions ratio are considered as cladding materials to fabricate a dense composite clad surface. Single tracks are formed using 15.92 × 104 w/cm2 laser power density and three different laser scanning speeds of 200,400 and 600 mm/min to analyze the clad height, aspect ratio, dilution rate and average contact angle of the track. Further, area clads are fabricated for different powder compositions of the cladding materials. The clad layer thickness are found to be decreases with increase in laser scanning speed and rise in the percentage of ilmenite (Fe-TiO3). The formation of different microstructure in the clad as well as interface zone are observed. With the increase in the percentage composition of ilmenite with cerium and lanthanum leads to the refined and coarser grain microstructure with unique structure are found which enhance mechanical properties like wear and hardness of the clad. Some of the important microstructure like dendritic, lamellar, flower, grit type and long needle type are found on the clad surface. The formation of unique chemical compound such as Ti3O, La2O3, Ti2B5, LaTi21O38, Ce3B2N4, Fe4N, TiN, La3BO6, and Fe-TiO3 are observed through the XRD analysis. Micro hardness of the clad surface are found to be increases approximately five times to the substrate at the clad with the increase in percentage composition of RE element, but found to be decrease drastically as passing through the intersection zone due to intermixing phenomena of clad and the substrate. It is observed that with higher percentage composition of RE result decrease in the reduction of the coefficient of friction approximately thrice to that of the cladded sample as compare to base (Ti6Al4V), which improve the wear resistance of the clad material. However there are minor amount of defects like micro crack are found on the clad and wear at the disk are occurred due to ploughing and cutting observed through track analysis.