X-RAY STUDY OF AGED AU-NI ALLOYS
Abstract
AN INVESTIGATION WAS MADE OF THE AGE-HARDENING PROCESS OF AU-NI ALLOYS BELOW 225 DEGREES C. PREVIOUS DATA INDICATE THAT AGING BELOW 225 C MGHT INVOLVE CLUSTERING OF ATOMS. THESE CLUSTERS MAY CONSIST OF GROUP OF LIKE ATOMS (EITHER AU OR NI) OR, STRUCTURALLY, REGIONS OF HIGHER GEOMETRIC ORDER. MEASUREMENTS WERE MADE OF THE RELATIVE SHIFTS OF THE X-RAY DIFFRACTION PEAKS DURING AGING. THE 0.03 X 1 X 0.75 IN. SPECIMENS HAS A 36 AT-( NI AND 64 AT-( AU COMPOSITION. THE MEASURED VALUE OF THE RELATIVE SHIFTS OF THE (200)-(111) LINE SEPARATION AMOUNTED TO -0.07 DEGREES, WHILE THE MEASURED VALUE FOR THE (400)(222) LINE SEPARATION WAS +0.05 DEGREES. THESE RELATIVE LINE SHIFTS SUGGESTED THE FORMATION OF STACKING FAULTS DURING AGING TREATMENT. RESULTS SUGGEST THAT THE QUENCHED-IN VACANCIES MIGRATE AND COAGULATE DURING AGING TO FORM PLATELETS ON ONE OR THE OTHER OF THE CLOSE-PACKED PLANES OF THE LATTICE. COLLAPSE OF THE PLATELETS RESULTS IN THE FORMATION OF TETRAHEDRAL STACKING FAULTS WHERE NI ATOMS MIGHT AGGREGATE FROM CHEMICAL ENTERACTION BETWEEN SOLUTE ATOMS AND STACKING FAULTS
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 1960
- Accession Number
- AD0250502
Entities
People
- J.m. Sivertsen
- R.c. Sundahl
Organizations
- University of Minnesota