Development and Study of Extrusion 3D Printing and Post-Processing Modes for Metallic Articles from Alloys of the Co – Ni – Al System

Abstract

The possibility of fabricating articles from a Co37Ni36Al27 alloy by extrusion 3D printing followed by thermal debinding and sintering is demonstrated. The printing is carried out from metal-polymer compositions (MPC) based on two different powder fractions (71 – 125 μm and < 71 μm) obtained by mechanical alloying (MA) in an attritor. The porosity and the magnetic characteristics of the samples are shown to be controllable by changing the MPC powder fraction and by varying the sintering temperature. The porosity decreases by about a factor of 1.5 and the thickness of the necks (metallic bonds between the particles) increases by about a factor of 17. The porosity is treated as the main characteristic reflecting the sintering intensity and, consequently, the quality of the sample structure. Adecrease in the coercive force by approximately 1.5 times and an increase in the saturation magnetization by approximately 1.3 times are shown to accompany the decrease in the number of structural defects. The structure of the sintered samples is represented by β-, γ-, and γ′-phases, which indicates a low rate of cooling with the furnace.