NATO advanced research workshop on measurement of residual and applied stress using neutron diffraction; held in Oxford, England on 18-22 March 1991. Technical report

Technical Report · Mon Apr 01 04:00:00 EST 1991

OSTI ID:5360867

Winholtz, R A

In two phase or composite materials it is possible to determine both the macrostresses in the material and the average microstresses present in each phase. The stress equilibrium relations allowing this separation are outlined. It is shown that errors in the unstressed lattice parameter lead to errors in only the hydrostatic component of the stress tensor. It is thus possible to accurately determine the entire deviatoric macrostress and microstress tensors without the unstressed lattice parameters of the individual phases. Two examples of the usefulness of macrostress and microstress measurements are given. In a SiC-TiB2 microcracking ceramic composite large hydrostatic microstresses develop during consolidation due to differential thermal contraction. Microcracks form during stressing, relaxing the thermal microstresses. Measurements of this relaxation have helped quantify the toughening in this system associated with microcracking. Measurements in both the ferrite and cementite phases of 1080 steel during low cycle fatigue show the proportion of the applied load carried by each phase. These results show that as the material yields in both tension and compression, the carbides take a higher fraction of the load and thus the stress range experienced by the carbide phase is much higher.

• Research Organization: Northwestern Univ., Evanston, IL (United States). Dept. of Materials Science
• OSTI ID: 5360867
• Report Number(s): AD-A-235103/9/XAB; TR--30; CNN: N00014-80-C-1116
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ALLOYS
BORIDES
BORON COMPOUNDS
CARBIDES
CARBON COMPOUNDS
COHERENT SCATTERING
COMPOSITE MATERIALS
CONTRACTION
DIAGRAMS
DIFFRACTION
FATIGUE
FERRIMAGNETIC MATERIALS
FERRITES
FRACTURE MECHANICS
HYDROSTATICS
INTERNATIONAL ORGANIZATIONS
IRON ALLOYS
IRON BASE ALLOYS
IRON COMPOUNDS
MAGNETIC MATERIALS
MATERIALS
MECHANICAL PROPERTIES
MECHANICS
MEETINGS
NATO
NEUTRON DIFFRACTION
OXYGEN COMPOUNDS
PHASE DIAGRAMS
RESIDUAL STRESSES
SCATTERING
SILICON CARBIDES
SILICON COMPOUNDS
STEELS
STRESS ANALYSIS
STRESSES
TENSORS
TITANIUM BORIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS