Application of AES to failure analysis of commercial nickel and copper alloys

Abstract

Cracking, tearing and embrittlement of metals and metal alloys is often a result of segregation of impurity elements to a particular site such as a grain boundary. In many cases, the analytical procedures or instruments available to a laboratory do not provide sufficient resolving power to allow observation of the segregated species. This paper discusses the application of a particularly sensitive technique that has proven to be of major value. In this paper, a number of practical examples including the failure of commercial materials have been studied by Auger electron spectroscopy, and the segregating element or elements identified. In most cases, the fracture surfaces generated in situ in the high vacuum instrument were examined; however, for one example, useful information of segregation to grain boundaries was obtained on a specimen fractured at high temperature in air and shipped hundreds of miles to the AES instrument. The Auger analyses are supplemented by bulk chemical analysis and by SEM observation of the fracture surfaces. The examples described were evidenced by a lack of hot ductility of 80%Ni-20%Cr, 70%Cu-30%Ni and 60%Ni-40%Cu alloys, and embrittlement of a 90%Cu-10%Ni alloy and commercially pure nickel. © 1981.