Vol.:(0123456789) 1 3 Metals and Materials International https://doi.org/10.1007/s12540-019-00375-3 Post‑Processing Efects on Sur face Properties of Direct Metal Laser Sintered AlSi10Mg Parts Binnur Sagbas 1 Received: 1 March 2019 / Accepted: 10 July 2019 © The Korean Institute of Metals and Materials 2019 Abstract Direct metal laser sintering is a powder bed fusion type additive manufacturing (AM) method. It provides opportunity to create near net shape parts layer-by-layer. Because of poor surface quality post processing operations are required. This paper investigates the efect of surface fnishing operations such as abrasive blasting, shot peening and polishing on surface texture properties and green tribological behavior of direct metal laser sintered AlSi10Mg parts. 2D and 3D surface rough- ness characterization, density and hardness measurements were implemented. Ball-on-disc wear tests were applied under 10 N load with palm oil and soybean oil as green lubricants. Petrol based, commercial machine oil was used for control. The results revealed that post processing operations afected surface texture and tribological properties of the samples. Abrasive blasting increased surface hardness to the 187 HV, while it was measured as 178 HV and 124 HV for shot peening and pol- ishing processes respectively. Average surface roughness Ra, was measured as 18.71 µm for shot blasted surface. This value recorded as 5.39 µm for shot peened and 1.39 µm for polished surfaces. Minimum wear rate was calculated as 3.88 × 10 −4 mm 3 /Nm for shot peened surface with palm oil while maximum was calculated as 7.92 × 10 −4 mm 3 /Nm for polished surface with MO lubrication. Palm oil and soybean oil represented superior lubricating properties than petrol based commercial machine oil for all surfaces. It can be concluded that surface post processing has important efect on texture properties of metal AM parts. Moreover, vegetable oils are promising lubricants for increasing tribological properties of AM surfaces. Keywords Additive manufacturing · Blasting · Green tribology · Shot peening · Vegetable oil 1 Introduction Additive Manufacturing is a developing technology and has emerging trend in manufacturing area. Direct metal laser sintering (DMLS) is a kind of additive manufactur- ing (AM) method which uses powder bed fusion technology for building up near net-shape parts. The method creates metal parts from CAD data by melting the metal powders with laser source layer-by-layer. This technology has been detail explained in [1, 2]. Because of their good mechani- cal, dynamic, thermal properties and good corrosion resist- ance AlSi10Mg is one of the most widely used materials in DMLS applications [3]. By having good strength-to-weight ratio these materials are ideal for the load carrying parts in aerospace and automotive industries [4, 5]. DMLS provide great opportunity for building up complex geometries however surface quality is still concern. Surface roughness of as built parts may be in the range of 8–25 µm. Various methods have been discussed in literature studies for improving surface quality of the AM parts. There are lots of process parameters such as laser power, hatch distance, scan speed, scan strategy, beam diameter etc. optimization of these parameters is an efective way for increasing surface quality [6–8] Another method for surface quality improve- ment is post processing operations such as abrasive blasting, chemical etching [9], shot peening, polishing, machining etc. [10–12] Shot peening is a kind of cold plastic deforma- tion process in which compressive stresses are produced by spherical metallic or ceramic shots. These stresses cause plastic deformation of the surface and change mechani- cal strength, texture and hardness of the surface without material removal [13, 14]. Shot blasting and polishing are post processes which depend on material removal from the surface by abrasives. In shot blasting metal or glass shots * Binnur Sagbas bsagbas@gmail.com 1 Department of Mechanical Engineering, Yildiz Technical University, 34349 Besiktas, Istanbul, Turkey