Journal of Applied Mechanical Engineering

Microstructure analysis of maraging steel X3NiCoMoTi 18-9-5 produced by additive manufacturing

Joint Event on 2^nd International Conference on Advanced Robotics, Mechatronics and Artificial Intelligence & 3^rd International Conference on Design & Production Engineering

December 03-04, 2018 | Valencia, Spain

Ludmila Kucerova

University of West Bohemia, Czech Republic

Keynote: J Appl Mech Eng

Abstract:

Maraging steel X3NiCoMoTi 18-9-5 could be processed not only by conventional casting and heat treatment, but also by additive technology of laser direct melting. Input material for used selected laser melting (SLM) technology is metal powder. The powder used for additive manufacturing was analyzed to determine distribution of alloying elements within individual powder grains. Microstructure and mechanical properties of SLM build were determined in as-printed state and also after printing and subsequent heat treatment by either solution annealing or precipitation hardening. The microstructure in as-build state consisted of very fine cells of solid solution with thin films of retained austenite placed at the cell boundaries. An average tensile strength of 1050 MPa and total elongation of 8% was obtained in these samples. Solution annealing led to complete transformation of retained austenite to martensite and disappearance the original cellular microstructure. The resulting tensile strength was slightly below 1000 MPa, accompanied by total elongation of 9% and hardness of 328 HV 0.1. Precipitation hardening of as-built samples resulted in partial dissolution of the cells and an increased volume fraction of austenite. The ultimate tensile strength of hardened samples was nearly twice as high as in the as-built state reaching 1800 MPa. The microstructures and mechanical properties were compared with conventional maraging steel with the same chemical composition, sold under commercial name Vaco 180. In-situ observation of the straining of maraging steel in as-build condition was carried out, demonstrating the effect of metallurgical defects on failure initiation in additive manufactured steel.

Recent Publications

1. Monkova K, Zetkova I, Ku?erová L, et al. (2018) Study of 3D printing direction and effects of heat treatment on mechanical properties of MS1 maraging steel. Arch Appl Mech. 1-14.

2. Ku?erová L and Zetková I (2016) Metallography of 3D printed 1.2709 tool steel. Manufacturing Technology 16(1):140-144.

3. Tan C H, Zhoua K, Ma W, et al. (2017) Microstructural evolution, nanoprecipitation behavior and mechanical properties of selective laser melted high-performance grade 300 maraging steel. Mater. Des. 134:23???34.

4. Mutua J, Nakata S, Onda T, et al. (2017) Optimization of selective laser melting parameters and influence of post heat treatment on microstructure and mechanical properties of maraging steel. Mater. Des. 139:486???497.

Biography :

Ludmila Kucerova completed her PhD in the year 2006 and habilitation in 2011 at University of West Bohemia in Pilsen. She is Head of Laboratory of Metallography and Head of the research program forming technologies in regional technological institute of UWB in Pilsen. She has published more than 35 papers in journals in WOS/Scopus. Her research work deals with the relationship between processing parameters, microstructure and mechanical properties of advanced high strength steels and she has been lately involved also in material analysis of additively manufactured metals.

E-mail: skal@rti.zcu.cz