Microstructure and Shape Memory Properties of Cu-12.5Al-xMn Alloy Produced by Additive Manufacturing with Powder Core Wire

In this work, high alumina Cu-12.5Al alloy was selected as the base alloy, in which a different Mn content was added to prepare the powder core wire with a structure resistant to element burning. Arc melt deposition process was applied to produce Cu-12.5Al- x Mn( x :1,2,3,4,5wt.%) alloy. The micromorphology, phase composition, grain size, and shape memory properties are studied. Results show that the shape recovery rate of Cu-12.5Al- x Mn alloy is maintained at more than 65% under 4% pre-strain, and it reaches the highest when the Mn content is 3wt.%. At the same time, the shape recovery rate of the Cu-12.5Al-3Mn alloy has reached 84.43% under 6% pre-strain. In addition, the alloy completed the bending test under 10% pre-strain and had a shape recovery rate of 64.93%. According to the analysis, the shape memory properties are directly related to the grain refining effect of the special heat and mass transfer behavior of “melt droplets wrapped with unmelted particles” in the powder core wire. It is also affected by structure transformation, the number of martensitic populations, and its order degree.