ORNL-2106 - the Molten Salt Energy Technologies Web Site

AUP PROJECT PROGRESS REPORT
0.09 mg/cm2. The weight losses of several freshly
cleaned specimens tested in water at various tem-
peratures for 15 min are presented below:
Temperature of Weight Loss
Water (OC) (mg/cm2)
30
50
80
100
0.243
0.271
0.309
0.326
Work was continued on the development of pro-
tective coatings and on cladding of the material. A
techniqe was developed for producing a bright
surface, which involves a two-step treatment with
concentrated phosphoric acid and acetone. The
bright surface tarnished slightly when exposed to
air, but it was stable at 3OOOC md for long periods
at lower temperatures. Specimens with surfaces
prepared by this method were roll clad with 2s alu-
minum and AZ31 magnesium alloy. The 25 alumi-
num-clad material produced a brittle bond, while
1 74
the AZ31 alloy failed to bond even to itself.
In order to further evaluate the mechanical prop-
erties of the 20% Li-80% Mg alloy, more sheet
specimens were needed. A 0.250-in. sheet was
mechanically clecmed of mill scale and corrosion
products, given the phosphoric acid-acetone treat-
ment, and hot rolled at 25OOC to a thickness of
0.070 in. A 30-min soak at 3OOOC straightened the
sheet. New specimens were machined from this
sheet and kept under mineral oil until tested. The
tensile data obtained for the new sheets are com-
pared with the data for the old sheets in Table
3.3.10 and the rupture data are compared in Table
3.3.11, Fixtures are being designed to test this
alloy at constant temperature, in a protective
medium of mineral oil, without the film produced by
phosphoric acid-acetone treatment.
Powder metallurgy was investigated as a dif-
ferent approach to fabrication of the shield ma-
terial. Lithium oxide was chosen as the lithium
source, being the most stable of the lithium
compounds and possessing the highest melting
TABLE 3.3.10. TENSILE DATA FOR 20% Li-80% Mg ALLOY SHEET
Density: 1.44 g/cm 3
Average Average
Sheet Temperature Elongation Tensile Strength Yield Strength
Specimen
(Or-) (%I (psi) (psi)
Old Room 35 12,500 11.230
New Room 48 12,775 10,650
0 Id 200 45 3.000 2,970
New 200 94 3.200 2.940
TABLE 3.3.11. RUPTURE DATA FOR 20% Li-SOX Mg ALLOY SHEET
All tests at mom temperature
Stress: 3000 psi
Sheet Elongation Rupture Life
Specimen
Coating
(%I (hr)
Old None 48 125
Grease 90 315
HN03 dip and grease 100 220
New Phosphoric acid, acetone, and grease 32 1050
Grease 35 566
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