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Accession Number:
AD0623844
Title:
EFFECT OF ELASTIC AND PLASTIC DEFORMATION ON THE MARTENSITE TRANSFORMATION IN 25% NI MARAGING-ALLOY SINGLE CRYSTALS.
Descriptive Note:
Final technical rept.,
Corporate Author:
CARNEGIE INST OF TECH PITTSBURGH PA DEPT OF METALLURGICAL ENGINEERING
Report Date:
1965-11-01
Pagination or Media Count:
188.0
Abstract:
The effect of the magnitude and temperature of elastic and plastic deformation prior to transformation on the burst transformation characteristics of a 25 Ni maraging alloy was determined systematically. Uniaxial tensile strain equal to or less than the Luders strain caused an 8 to 12C rise in the burst temperature, M sub b, of single crystals of various orientations that were strained at 0C, 20C, 120C, or 220C prior to transformation. When the prior plastic strain exceeded the Luders strain, a 2 to 3C decrease in M sub b was observed for each 0.1 increment of glide strain in excess of the Luders strain, and the amount of transformation product formed at M sub b was observed to decrease linearly with increasing plastic strain. In deformed single crystals the majority of the martensite plates formed along four 259 habit plane variants that grouped about a 110 direction that was 35.3 degrees from both the pole of the primary and the conjugate slip planes and 60 degrees from the primary slip direction. In single crystals transformed under an elastic compressive load, a decrease in M sub b was observed. The thickness of the crystal increased if the elastic compressive stress was less than 3 Kg.sq mm. and decreased if the stress was greater than 3 Kg.sq mm.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
