Microstructure and performance of the laser melted aluminum bronze layers with and without using activator

In the present research, the surface-melted aluminum bronze were manufactured by laser remelting technology. The microstructure and properties of the melted layers with and without using activator were investigated. With increasing laser power, the width and depth of the melted layer increased, and the grain size of the melted layer became coarser due to the higher heat input and larger molten pool volume. Under the same conditions (i.e. laser power of 1000 W), the width and depth of the melted layer could be reduced and increased, respectively, with the use of the activator. In particular, the depth of melted layer increased by nearly 50%. Furthermore, to obtain the same penetration of the melted layer, the addition of the activator could reduce the heat input, which led to the decrease of grain size. The relatively small grain size and high dislocation density could improve the hardness and tribological behavior of the melted layers. (paper)