Accession Number : AD0670208

Title :   TENSILE PROPERTIES OF NEARLY INTERSTITIAL-FREE SUBSTITUTIONAL IRON ALLOYS.

Descriptive Note : Scientific summary rept. 1 Sep 62-31 Dec 66,

Corporate Author : UNIVERSITAET DES SAARLANDES SAARBRUECKEN (WEST GERMANY) INST FOR METAL PHYSICS AND METALLURGY

Personal Author(s) : Dickenscheid,W.

Report Date : FEB 1968

Pagination or Media Count : 92

Abstract : The report deals with the influence of substituted alloying atoms on the tensile properties and plasticity of iron with very low interstitial content. The specimens - wires of 1 mm diameter - were purified in an atmosphere of palladium-filtered high purity hydrogen. Gas analysis showed that interstitial contents were well below the ppm. limit. Tensile properties of the following alloy systems were determined between room temperature and -100C: Fe-Mo, Fe-P, Fe-Si, Fe-Al and Fe-Ni. At sub-zero temperatures Fe-Si alloys showed a decrease of the alloy hardening. Fe-Al and Fe-Ni alloys even displayed 'alloy softening', i.e. a decrease of the yield stress at increasing alloy concentrations. Phosphorus causes a very strong alloy hardening. Some small part of the phosphorus atoms seems to be in interstitial positions instead of substitutional ones. A method of form analysis was applied to the recorded stress-strain diagrams. Three stages of the deformation process in polycrystalline specimens separated by transition points at about 2% and 7% strain could be traced. The second and third stage resemble some kind of dynamic recovery. The elementary deformation processes seem to take place in an environment of higher dislocation density. Activation volumes that were determined for some alloys correspond to the latter conclusion. (Author)

Descriptors :   (*IRON ALLOYS, TENSILE PROPERTIES), PLASTIC PROPERTIES, MOLYBDENUM ALLOYS, PHOSPHORUS ALLOYS, SILICON ALLOYS, ALUMINUM ALLOYS, NICKEL ALLOYS, STRAIN(MECHANICS), IMPURITIES, PURIFICATION, THERMAL ANALYSIS, STRESSES, FRACTURE(MECHANICS)

Subject Categories : Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE