V.4 - Effect of Laser Surface Treatment and Work Hardening on the Fretting wear Resistance of Zr-2.5Nb Alloy at High Temperature

Abstract

Fretting wear occurs between two contacting surfaces having oscillatory relative motion of small amplitude. This type of damage has great economical and safety impact on the operation of nuclear reactors, because a large number of their components are subjected to flow induced vibrations. Zirconium alloys are highly desirable for nuclear applications because of their high corrosion resistance and transparency to thermal energy neutrons. Their wear resistance is, however, much lower than other nuclear-grade materials, for example, nickel alloys and stainless steels. For nuclear applications, the use of surface coatings is restricted by some basic requirements to ensure that the coating material does not absorb neutrons, reduce reactor activity, or include elements that produce long-lived radioisotopes. Therefore, the objective of this investigation is to explore the potential of increasing the fretting wear resistance of Zr-2.5Nb alloy by only modifying the material surfaces through cold working and laser surface heating and glazing.