Age Strengthening of Gray Cast Iron: Kinetics, Mechanical Property Effects
Previous work by Nicola and Richards (Nicola, 1999) has demonstrated that there is statistically significant age strengthening in most gray cast iron alloys. Differential scanning calorimetry studies have revealed two significant exothermic reaction peaks in fully aged gray iron specimens. Heating to a temperature above 250 ░C does not produce a significant change in tensile strength whereas heating above the second exothermic peak lowers the tensile strength proportionally with the original age strengthening. It is further shown that the strengthening effect returns upon re-aging. Precision hardness measurements have revealed that Brinell hardness also increases with age strengthening; however, not as much as the tensile strength, which makes the tensile-strength-to-Brinell-hardness ratio increase with aging time.
V. Richards and D. C. Van Aken, "Age Strengthening of Gray Cast Iron: Kinetics, Mechanical Property Effects," Transactions of the American Foundry Society, American Foundry Society (AFS), Jan 2003.
Materials Science and Engineering
Keywords and Phrases
Age Strengthening; Exothermic Reaction Peaks; Gray Cast Iron Alloys; Kinetics
Article - Journal
© 2003 American Foundry Society (AFS), All rights reserved.