Alessandro Ascari ∗ Giampaolo Campana Department of Industrial Engineering University of Bologna Bologna, Italy, 40136 Email: a.ascari@unibo.it Email: giampaolo.campana@unibo.it ABSTRACT This article illustrates an experimental campaign aimed at assessing preliminary guidelines for the application of the laser in joining cellular-structured hybrid materials. In particular the target specimens exploited were all characterized by the pres- ence of an aluminum foam core and by an external skin, made in aluminum or in stainless steel. The goal of the present paper is to underline a global feasibility of laser joining of these ma- terials pointing out the role of the main process parameters and to suggest some original techniques which could be adopted in order to improve the overall quality of the joint. The experience described pointed out that, when dealing with this kind of mate- rials, the role of the laser can be dual: in case of high energy density applications it can be used for local fusion of the work- piece, as in traditional welding, while in low energy density ones the radiation can be exploited as a controlled heating source for promoting local thermal actions particularly on the cellular por- tion of the material. NOMENCLATURE E Process energy [J ] P Laser power [ W ] P dens Laser power density [ W /mm 2 ] D Tube diameter [mm] d Laser spot diameter [mm] ∗ Address all correspondence to this author. ω Specimen rotational speed [rpm] v Welding speed [m/min] t Process time [s] t int Material-radiation interaction time [s] INTRODUCTION Metal foams represent a relatively modern class of materi- als characterized by the fact that, from a macroscopic point of view, their structure is not dense and continuous, but it is con- stituted by large pores separate from one another by thin metal walls. Many metallic materials can be properly manufactured in order to gain a cellular structure but, without any doubt, the most common ones are aluminum and its alloys. Considering their structure metal foams are characterized by several proper- ties which differentiate them from traditional dense materials: low density, high stiffness to weight ratio, high energy absorp- tion during deformation and good thermal characteristics. Ac- cording to these peculiarities the industrial interest towards these materials has increased in the last decades and many researchers stressed on the most various manufacturing aspects concerning their design, production and manufacturing techniques ( [1], [2] and [3]). One of the most interesting and challenging applica- tions of those materials concerns the production of the so-called HMM (Hybrid Metallic Materials): in order to couple the ad- vanced characteristics of metal foams to traditional dense mate- rials, the idea is to produce industrial components characterized by an external dense skin, typically a thin sheet, filled in with a 1 Copyright c  2013 by ASME Proceedings of the ASME 2013 International Manufacturing Science and Engineering Conference MSEC2013 June 10-14, 2013, Madison, Wisconsin, USA MSEC2013-1057 APPLICATION OF LASER IN JOINING ALUMINUM FOAM HYBRID MATERIALS