Accession Number : AD0766586

Title :   Workhardening, Slip Band Formation and Crack Initiation During Fatigue of Titanium,

Corporate Author : DEUTSCHE FORSCHUNGS- UND VERSUCHSANSTALT FUER LUFT- UND RAUMFAHRT E V PORZ-WAHN (WEST GERMANY)

Personal Author(s) : Munz,Dietrich

Report Date : 1973

Pagination or Media Count : 17

Abstract : The workhardening behavior and slip band formation during fatigue were investigated up to the crack initiation phase of three titanium materials (IMI 115, Contimet 30, Contimet 35) having different impurity contents. The workhardening behavior was studied using fatigue tests with constant strain amplitude. At the beginning of the cyclic loading the stress amplitude decreased afterwards it increased again. The change in stress amplitude could be explained by the dependence of the thermal and the athermal flow stress components on the dislocation density. Similar as in bcc metals the worksoftening is due to an increase in the mobile dislocation density. At low frequencies the plastic strains resulted in the formation of slip bands. With increasing frequency the number and the intensity of the slip bands decreased. No slip bands were observed above 50 Hz. The crack initiated at low frequencies at grain boundaries, in slip bands or transcrystalline without any visible connection with slip bands. At higher frequencies only 'slipless' cracks occurred. (Author)

Descriptors :   (*TITANIUM, FATIGUE(MECHANICS)), HARDENING, MICROSTRUCTURE, FRACTURE(MECHANICS), CRACKS, WEST GERMANY

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE