Tensile strength of Nitinol flanges fabricated by laser rod end melting and immediate flange processing

Abstract

Nitinol is a shape memory alloy used for actuator applications. However, the connection between Nitinol wire and mechanical system via adhesive bonding or crimping could be weakened due to the exposure of joint in aggressive environments and temperature changes. Therefore, a process chain called laser rod end melting with immediate flange processing has been put forward and proven to fabricate all-in-one Nitinol flanges. According to previous work, there is a partially solidified preform connecting to the wire as the shaft, where the connection factures under tensile tests. In the present study, the effect of size of partially solidified preform on the tensile behavior was investigated on the cylindrical flanges with different flange heights. The results show that the partial preform volume increases with the flange heights, while the tensile strength becomes smaller when the flange height is too small. This suggests that it is important to maintain the mechanical strength of Nitinol flange by choosing the appropriate flange height.