Research Activity in Tribo-Mechanical Evaluations of Cobalt-based Alloys
Background
Stellite or cobalt-based alloys are well known for their excellent wear and corrosion resistance as well as high temperature strength. These alloys are generally used for cutting tools, hard-facing materials, corrosion resistant castings and gas turbine applications for aerospace, offshore, chemical processing, marine and steel making industries. Typical composition of these alloys can be found at www.stellite.com.
Tribo-mechanical properties of these alloys can not only be effected by the
selection and content of various alloying elements, but also by altering the
process conditions e.g. various forms of casting, post-cast processing and
other manufacturing routes such as laser cladding and HIPing. All of these
factors influence the microstructure and thus the tribological and mechanical
properties. A typical comparison of cast and HIPed microstructure is shown in Figure
1.
dentritic microstructure cast stellite 6 microstructure of HIPed stellite 6
Fig. 1, Microstructure of cast and HIPed cobalt-based alloys.
Current Research
This
project aims to consider the tribo-mechanical evaluations of some of these
cobalt-based alloys to deliver a thorough understanding of structure property
relationships and to optimise the design process. Figure 2 shows the
investigation methodology adapted to provide a thorough and generic
understanding of the performance of these alloys.