Abstract
D.Ing. (Mechanical Engineering)
Laser metal deposition (LMD) is one of the additive manufacturing technologies that is used
in the production of fully dense parts layer by layer. This innovative manufacturing process
shows real promise in reducing component fabrication time, cost and weight. One of the major
advantages of this technology is in the ability to manufacture components with multi-material
properties such as Functionally Graded Materials (FGM). FGM is a class of advanced materials
that combine the benefits of its component materials together as a whole, while minimizing the
problems produced by material property mismatch of the constituent materials. Several studies
have been conducted on FGMs processed by LMD. Most of these studies are on metal-ceramic
composites, however, there is a growing need for bimetallic components with different
properties along their axial or radial directions for modern engineering applications.
In this study, the laser metal deposition process was evaluated as a candidate for manufacturing
a compositionally graded bimetal material consisting magnetic and non-magnetic metals. The
materials used were 17-4PH powder, AISI 316L powder and AISI 316 substrate. Since this
study has not been done and there were no known models or strategies to follow in building
this particular FGM. Trial and error experiments were first adopted in selecting the process
conditions for building the FGM.
The trial and error experiments, referred to as preliminary study involved the production of 17-
4PH and AISI 316L clads. This was done primarily to evaluate the solidification behaviour of
the individual powders and also identify the process window that will successfully produce
fully dense clads with good bonding and wettability that are structurally harmonised. Based
on the findings of the preliminary studies, a set of parameters was obtained as a standard for
producing the compositionally graded composite...