Use of Alloy Additions to Prevent Intergranular Stress Corrosion Cracking in Aluminum Bronze

The general principles of equilibrium grain boundary segregation are applied to form a theory on the possible elimination of intergranular stress corrosion cracking in alpha aluminum bronze in steam. Various possible alloy additions are discussed in relation to their atom size, solubility, and tendency to react with steam. A theoretical selection of beneficial additions is made. Actual test results on several alloys containing a variety of additions are presented, illustrating good agreement of theory and results. The effects of the additions on transgranular ammonia cracking susceptibility are also discussed. A brief history of the application of laboratory results to field testing and actual application to the product is given. 3.7.2