Synthesis and characterization of nano structured Cu–Al–Mn shape memory alloy by mechanical alloying

In this study, Cu-based shape memory alloy (Cu-12.5%Al-5%Mn in %wt) was processed by mechanical alloying in different milling conditions (2.5, 5, 10, 15 and 25 h). Prepared powders were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). XRD results showed that increasing milling time leads to a reduction in crystallite size and an increase in lattice parameters. After 15 h of milling, the minimum crystallite size was found to be around 7 nm, and did not change upon further processing. SEM and TEM results showed that morphology of pre-alloyed powder changed with milling time from lamella to globular and the mean size of pre-alloyed powders was around 15 nm after 15 h of milling. EDX analysis results indicated a homogeneous distribution of Mn and Al elements within the Cu matrix.