Metallurgical Variables Influencing the Corrosion Susceptibility of P/M (Powder Metallurgy) 7091 Aluminum/SiCw Composite

摘要

Corrosion studies of a 20 v/o SiCw/P/M 7091 aluminum composite material were performed. The plate material which was heat treated to the T-6 and T-7 temper by conventional methods, showed preferential corrosion of the surface layers up to 2 mm thick. The regions of corrosion susceptibility were determined to be due to improper processing and thermal treatments. Cold worked regions due to extrusion were not completely removed by the conventional solution treatment and thus appeared as more corrosion susceptible. Large void volume fraction and excessive segregation of SiCw was also noted. Electrochemical, microscopic and analytical techniques were used in these investigations. Attempts were made to remove the cold worked regions and study the resultant corrosion properties. Attempts were made to remove the cold worked regions and study the resultant corrosion properties. A comparative analysis of these results is discussed. (Author)