ABSTRACT
References .....................................................................................................................................223
In 1907, Elwood Haynes developed a series of cobalt-chromium alloys suitable for tableware,
surgical instruments, laboratory equipments, analytical weights, and cutting tools to be used on
relatively soft metals [1]. In 1913, these cobalt-chromium alloys were placed on the market [1].
Determination of phase diagrams for various alloys systems was very active at the start of the
twentieth century, which allowed for the development of new alloys with many useful properties
[2]. After the initial application of the cobalt-chromium alloys and advances in phase diagrams,
various wrought cobalt-based alloys were developed that found extensive usage for such com-
ponents as forged turbine blades, combustor liners, and afterburner tailpipes [3]. The “cobalt crisis”
in the late 1970s increased the price of cobalt tremendously, hindering their continued development
and use. However, cobalt-based alloys offer unique combinations of properties, such as high-
temperature creep and fatigue strength, as well as resistance to aggressive corrosion and various
forms of wear. Properties such as these should secure the use of cobalt-based alloys now and in
the future.
