The structure and properties of grain boundaries in B2 ordered alloys

Technical Report · Mon Apr 16 04:00:00 EDT 1990

DOI:https://doi.org/10.2172/5722753· OSTI ID:5722753

Baker, I

This report covers the period from April 1, 1989 to March 30, 1990. During this period further extrusions of fine-grained alloys of FeAl and NiAl with different aluminum contents were produced. Thus far, researchers have (1) completed room temperature mechanical testing which shows that the yield strength, {sigma}{sub y}, of FeAl shows a minimum near Fe-45Al while that for NiAl increases with increasing (nickel-rich) deviation from stoichiometry; (2) showed that the grain boundary strengthening parameter, k, in the Hall-Petch relationship, {sigma}{sub y} = {sigma}{sub 0} + k d{sup {minus}{1/2}} (where {sigma}{sub 0} is the lattice resistance and d the grain size), in FeAl shows a minimum at Fe-45Al whilst in NiAl it decreases with increasing deviation from stoichiometry; (3) studied grain boundary chemistry in near-stoichiometric NiAl and FeAl using scanning Auger electron spectroscopy at Oak Ridge National Laboratory, with the aid of Mr. R.A. Padgett, Jr.; studied grain boundary chemistry using EDS and Z-contrast imaging on field emission gun high resolution scanning transmission electron microscopes; (5) continued in-situ straining experiments in the transmission electron microscope to examine dislocation/grain boundary interactions; (6) examined dislocation structures in lightly-deformed NiAl and FeAl and, based on observations in the latter, proposed a mechanism for transgranular fracture; (7) completed work which examines the effect of cooling rate following annealing on the strength and hardness of FeAl.

• Research Organization: Dartmouth Coll., Hanover, NH (United States). Thayer School of Engineering
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG02-87ER45311
• OSTI ID: 5722753
• Report Number(s): DOE/ER/45311-3; ON: DE92007467
• 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
ANNEALING
AUGER ELECTRON SPECTROSCOPY
CRYSTAL STRUCTURE
DEFORMATION
DOCUMENT TYPES
ELECTRON SPECTROSCOPY
FRACTURE PROPERTIES
GRAIN BOUNDARIES
HARDNESS
HEAT TREATMENTS
INDIUM ALLOYS
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL PROPERTIES
MICROSTRUCTURE
PALLADIUM ALLOYS
PLATINUM METAL ALLOYS
PROGRESS REPORT
SPECTROSCOPY
STOICHIOMETRY
YIELD STRENGTH