Internal Friction and Modulus Studies on Austempered Ductile Iron.
Abstract
Internal friction and modulus measurements were performed on three difference compositions of austempered ductile iron. These measurements were performed using a TA Instruments' Dynamic Mechanical Analyzer under a variety of thermal cycling conditions. The internal friction data exhibit the Snoek effect peaks at about 250 deg C. Using peak positions measured at different frequencies, the activation energy of the process was measured and found to average 31.9 kcal/mole. This is consistent with the activation energy of the diffusion of carbon in gamma-Fe (32 kcal/mole). The untransformed austenite was decomposed by holding at 400 deg C. After decomposition, the internal friction peak disappeared and the modulus increased 10 percent. These results confirm that the internal friction and reduced modulus arise from anelastic effects in the untransformed austenite phase.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1996
- Accession Number
- ADA306562
Entities
People
- Paul J. Cote
- Tammy Hickey
Organizations
- United States Army Armament Research, Development and Engineering Center