Study of dynamic behaviour via Taylor anvil test and structure observation of M300 maraging steel fabricated by the selective laser melting method

Abstract

This paper deals with the M300 high strength maraging steel fabricated via selective laser melting method. Mechanical properties especially microhardness and compressive yield strength of maraging steel in as-printed state were observed. The acquired data was implemented in Johnson-Cook constitutive equation used for numeric simulation, which showed the satisfactory correlation with the observed experiment. Dynamic behaviour under high strain rate (impact velocity reached 185 m.s-1)- 1 ) was investigated via Taylor Anvil Test. The experiment revealed structure and geometrical changes accompanied with the creation of characteristic funnellike and cylindrical areas on the deformed sample. Impacted sample forehead featured the increase of micro- hardness (465 HV) accompanied with structure changes. The structure in the funnel-like area exhibited the decrease of average grain size, which reached the minimum (3.1 mu m) in the vicinity of the impacted forehead. Closer analysis revealed that the high strain rate caused the increase of high fraction high-angle grain boundaries (50,8 %) and higher geometrically necessary dislocation density (52.77 1.m-- 2 ) in the funnel-like area.This paper deals with the M300 high strength maraging steel fabricated via selective laser melting method. Mechanical properties especially microhardness and compressive yield strength of maraging steel in as-printed state were observed. The acquired data was implemented in Johnson-Cook constitutive equation used for numeric simulation, which showed the satisfactory correlation with the observed experiment. Dynamic behaviour under high strain rate (impact velocity reached 185 m.s-1)- 1 ) was investigated via Taylor Anvil Test. The experiment revealed structure and geometrical changes accompanied with the creation of characteristic funnellike and cylindrical areas on the deformed sample. Impacted sample forehead featured the increase of micro- hardness (465 HV) accompanied with structure changes. The structure in the funnel-like area exhibited the decrease of average grain size, which reached the minimum (3.1 mu m) in the vicinity of the impacted forehead. Closer analysis revealed that the high strain rate caused the increase of high fraction high-angle grain boundaries (50,8 %) and higher geometrically necessary dislocation density (52.77 1.m-- 2 ) in the funnel-like area.