Accession Number : ADA306562

Title :   Internal Friction and Modulus Studies on Austempered Ductile Iron.

Descriptive Note : Final rept.,

Corporate Author : ARMY ARMAMENT RESEARCH DEVELOPMENT AND ENGINEERING CENTER WATERVLIET NY BENET LABS

Personal Author(s) : Hickey, Tammy ; Cote, Paul J.

PDF Url : ADA306562

Report Date : JAN 1996

Pagination or Media Count : 25

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.

Descriptors :   *AUSTENITE, *IRON, *DUCTILITY, *INTERNAL FRICTION, FREQUENCY, PEAK VALUES, MECHANICAL PROPERTIES, ELASTIC PROPERTIES, CARBON, CYCLES, HEATING, INSTRUMENTATION, DIFFUSION, ANALYZERS, DECOMPOSITION, THERMAL CYCLING TESTS, ACTIVATION ENERGY.

Subject Categories : Inorganic Chemistry
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE