Triple hopper powder feeder system for variable composition laser cladding

Abstract

In this work, a computer controlled triple hopper powder feeder system has been developed to feed and mix different elemental powders and incorporate them into the meltpool produced by a CO2 laser in such a way that the composition of the resulting clad layer can be accurately controlled and varied. Using this technique cladding a metallic surface by blowing powder into a laser generated melt pool has been successfully used to enhance the corrosion and mechanical properties of some materials. The cladding system enables variable composition clad tracks to be produced covering a substantial fraction of the possible compositions within the Al-Co-Fe ternary alloy system. The development of an automatic calibration system for determining the required powder flow rates is discussed. Analysis of the Al-Co-Fe system has demonstrated the potential of this new technique for characterising the corrosion and hardness properties of a complete ternary system. The results are presented in the form of ternary alloy maps for corrosion properties and hardness.