On slip transmission across grain boundaries and the brittle to ductile transition in Ni sub 3 Al and other L1 sub 2 alloys

Journal Article · Sat Jun 01 04:00:00 EDT 1991 · Scripta Metallurgica; (United States)

OSTI ID:5429653

Schulson, E M; Baker, I ^[1]

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1. Dartmouth Coll., Hanover, NH (United States). Thayer School of Engineering

This paper reports that, the authors began research on polycrystalline Ni{sub 3}Al about a decade ago. At the time Aoki and Izumi had already discovered that the addition of a small amount of boron effects a brittle-to-ductile (B/D) transition accompanied by a change from intergranular to transgranular fracture, and Liu, White and Horton were about to confirm the effect and to establish both that it does not occur on the Al-side of stoichiometry and that boron segregates to grain boundaries. Our objective was to produce a similar transition by refining the grains to below a critical size, as one of us had done in NiAl. This was unsuccessful. Of the undoped stoichiometric material we were studying, even 3 {mu}m grain-sized aggregates were brittle at room temperature. What the authors discovered, however, was something interesting about the yield stress. Grain boundaries, it turned out, contributed with the attendant improvement in ductility, albeit less than in boron-doped Ni-rich alloys, it allowed a different interpretation of the B/D transition. Specifically, we raised the possibility that the transition, instead of arising from an improvement in boundary cohesion, may arise from an improvement in the transmission of slip across grain boundaries.

• OSTI ID: 5429653
• Journal Information: Scripta Metallurgica; (United States), Journal Name: Scripta Metallurgica; (United States) Vol. 25:6; ISSN 0036-9748; ISSN SCRMB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals & Alloys-- Structure & Phase Studies
360103* -- Metals & Alloys-- Mechanical Properties
ALLOYS
ALUMINIUM ALLOYS
BORON ADDITIONS
BORON ALLOYS
BRITTLE-DUCTILE TRANSITIONS
CRYSTAL STRUCTURE
CRYSTALS
DOPED MATERIALS
FLOW STRESS
GRAIN BOUNDARIES
GRAIN SIZE
IRON ALLOYS
IRON BASE ALLOYS
MANGANESE ALLOYS
MANGANESE STEELS
MATERIALS
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
MICROSTRUCTURE
NICKEL ALLOYS
NICKEL BASE ALLOYS
PLASTICITY
POLYCRYSTALS
RESEARCH PROGRAMS
SIZE
STEELS
STOICHIOMETRY
STRESSES
TENSILE PROPERTIES
YIELD STRENGTH