Návrh experimentálního hodnocení makrostrukturních a mikrostrukturních vlastností dílů z technologie DED.

Abstract

This bachelor thesis focuses on the study of the integrity and microstructural characteristics of bimetallic deposits created using Directed Energy Deposition (DED) technology. The main objective of the work is to evaluate the metallurgical bond between 316L stainless steel and an ER70S carbon steel substrate in relation to the process parameters. The theoretical part describes the principles of the DED method, its specifics in the production of multi-material structures, and the classification of typical process defects such as LoF or porosity. The experimental part is focused on the macroscopic and microscopic evaluation of the welds and mechanical testing. Using image analysis methods, the presence of pores is quantified, and the dilution rate is calculated, which significantly affects the chemical composition of the transition zone. Microstructural analysis is dedicated to observing phase changes, crystallization characteristics, and monitoring the epitaxial grain growth at the interface of both materials. The mechanical performance of the bimetallic structure is assessed via a range of destructive testing methods across the joint to establish strength characteristics and the failure mechanism. The results of the work provide insight into the stability of the DED process during the formation of heterogeneous joints and identify critical factors affecting their final integrity.