Microstructure optimization of cold sprayed M2052 alloy using post-processing heat treatment for tailoring damping capacity

Abstract

Cold spray (CS) has been attracting an increasing interest due to low heat input, which avoids grain growth and high thermal stress. This feature is beneficial for high damping Mn-Cu alloy through limiting oxidation and formation of hot cracks. However, high dislocation density formed because of extensive plastic deformation, pores, and cracks result in the low damping capacity in the as-deposited Mn-Cu alloy. New strategy was introduced for improving damping capacity in cold sprayed Mn-20Cu-5Ni-2Fe (M2052 at%) alloy with different particle sizes (below 25 μm and between 15 and 53 μm). The 15–53 μm powder has high yield strength and plastic deformation resistance, which leads to a large number of defects and non-bonded interface between powders due to insufficient plastic deformation. Ageing treatment at 420 °C leads to spinodal decomposition of the fcc-austenite, and the formation of Mn-rich matrix and Cu-rich nanoscale network structure is found. Under the same ageing conditions, the spinodal decomposition level of the fcc-austenite in the CS M2052 alloy with the particles of 15–53 μm is higher than that with the particles of < 25 μm, which results from the difference in the grain size. As a result, the damping capacity in the CS M2052 samples with particle size of 15–53 μm is higher compared with the CS M2052 sample with particle size of < 25 μm. There is a significant increase in the damping capacity in the CS M2052 samples after HIP treatment, which can effectively reduce the internal defects and improve the bonding properties between powders.

Graphical abstract