Akademik Veri Yönetim Sistemi
Tezin Türü: Yüksek Lisans
Tezin Yürütüldüğü Kurum: Politecnico di Milano, SCHOOL OF INDUSTRIAL AND INFORMATION ENGINEERING, Department of Mechanical Engineering, İtalya
Tezin Onay Tarihi: 2021
Tezin Dili: İngilizce
Öğrenci: Arda SÜREN
Asıl Danışman (Eş Danışmanlı Tezler İçin): Ali Gökhan Demir
Eş Danışman: Leonardo Caprio, Bedri Onur Küçükyıldırım
Özet:
Laser powder bed fusion technology is a type of additive manufacturing that builds the products layer by layer. Each layer is completely melted with a laser source and it is followed by solidification. The LPBF is a very advantageous technology to build complex structures with its various choices of material resulting in outstanding performance. In recent years the effect of emission strategy is started to be investigated from various aspects such as productibility or melt pool stability. The effect of emission strategy on different properties is also being studied in this thesis work. In this thesis, two different materials are used. AISI 310S and Inconel 625 chosen to be the two materials processed by the LPBF technique due to their high corrosion resistance at high temperatures and good mechanical properties such as YS's reaching up to 300MPa for AISI 310 and 490MPa for Inconel 625. It has been stated with different studies that AM could be an outstanding choice of production of heat exchangers due to generic design, which could result in increased efficiency, this study is focussing on the LPBF technique for the production of a recuperative burner. Changing the emission strategy throughout the deposition of the final product could lead to a uniform structure due to the stabilization of the melt pools. To this end, both materials have been used to produce samples made of a different set of combinations of different emission strategies, hatch distance and scanning speed to understand the effect of the emission strategy on the two different alloys. A customized LPBF system has been used. The SLM machine used in this system is 3DNT LLA150. Density, porosity, microstructure, microhardness and compression properties of produced samples have been investigated throughout the experiment campaign. The results and the effect of the different sets of parameters have been analyzed with Minitab software using ANOVA. The materials have been successfully deposited with the mean porosity values of 0.2% and 0.9% respectively for AISI 310s and Inconel 625. In terms of compression characteristics of the studied materials, the influence of the emission technique was insignificant. Though it has been shown to be significant for density as predicted. Hatch distance and scanning speed appear to impact the porosity of Inconel 625 samples. Increasing the scanning speed and hatch distance, as expected, resulted in a decrease in relative density and, as a result, increased porosity. The microhardness analysis revealed that none of the studied factors has a significant influence. The mean compressive yield strengths are 600.9 MPa and 702.9MPa respectively for AISI310S and Inconel 625 indicating that both materials are promising to be produced by LPBF for the recuperative burner. Yet further analyzes are required to understand the materials characterization at high temperatures.