ORIGINAL ARTICLE Surface engineered AlMn alloy using laser surface alloying for wear resistance Moera Gutu Jiru 1 & Balkeshwar Singh 1 Received: 19 December 2019 /Accepted: 28 July 2020 # Springer-Verlag London Ltd., part of Springer Nature 2020 Abstract Laser beam applications for surface modification of engineering materials get high attention in research and industries due to superior surface performance for wear and corrosion resistance. In this work, laser surface alloying of aluminum plate with manganese metal powder has been successfully achieved using a continuous-wave CO 2 laser. The result shows improved surface hardness up to 121 HV while substrate material hardness has been 33 HV. The pin-on-disc wear test at loads of 10 N revealed the reduction by 30% due to manganese alloying. The friction coefficient of AlMn alloyed has been minimum as 0.34 while unalloyed aluminum substrate materials have been 0.62 less than unalloyed substrate materials. The depth of laser alloyed has been increased with laser power. The effect of sliding speed on friction coefficient has also been investigated. The higher sliding speed of 2 m/s has the least friction coefficient. The worn surface morphology indicated the different formation of wear mechanisms including adhesive wear and abrasive wear formations. Microstructure and surface morphology have been studied which displayed a good metallurgical bonding without defects. Keywords Laser surface alloying . Wear resistance . Composite . Hardness 1 Introduction Aluminum and its alloys have great potential for application in aerospace and automotive industries because of low cost, lightweight, and good strength. Recently, laser technology has been applied for the surface modification of material by alloying. The laser surface alloying is one of the three prom- inent methods of surface modification by adding external ma- terial to the substrate, the other two being laser dispersing and laser cladding [1]. In laser dispersing, hard ceramic particles are dispersed in the matrix of the base metal to make a com- posite structure [2, 3]. In laser cladding, a layer of the same or different material is deposited on the substrate surface to form a proper metallurgical bond [4, 5]. In laser surface alloying, the external material is diffused beneath the surface of the substrate to form the beneficial alloys. First, coating alloying material on substrate material by different methods like elec- trolysis followed by melting and solidification [6]. There is also a method of using a binder for pre-place the alloying material on a substrate then laser beam melting [7]. The alloying material can also be kept on the surface in the form of a powder or injected either co-axially with the laser beam or from the side [8, 9]. The alloying material can also be fed in the form of a wire [10, 11]. There have been several attempts for laser surface alloying and laser dispersing in the aluminum substrate. A 2-kW Nd- YAG laser was employed for alloying a powder composed of 96 wt% WC, 2 wt% Ti, and 2 wt% Mg at different traverse speeds in a substrate of sand cast aluminum A-356 alloy, which improved the wear resistance of the alloy [12]. A pulsed Nd: YAG laser with a maximum mean laser power of 400 W was employed to melt the nickel layer along with the substrate A356 aluminum alloy to form an alloyed layer on the surface which improved the hardness and wear resistance of the alloy [13]. Laser alloying of pure titanium powder (99.8%) mixed with chemical binder coated uniformly with 0.5-mm thickness on 99% pure aluminum substrate was carried out using con- tinuous mode CO 2 laser (Orion ® 3015, LVD makes) with * Moera Gutu Jiru jirata2010moti@gmail.com Balkeshwar Singh balkeshwar71@rediffmail.com 1 Department of Mechanical Design and Manufacturing Engineering, Adama Science and Technology University, Adama, Ethiopia The International Journal of Advanced Manufacturing Technology https://doi.org/10.1007/s00170-020-05844-3