Masters Theses


"The objective of this investigation was twofold: 1) to determine the effect of the quench-to-artificial aging delay period on the exfoliation corrosion of 7178 aluminum alloy subsequently aged at 250F for 24 hours and 2) to determine the effect of an initial aging treatment at 212F on the tensile properties and exfoliation of 7178 aluminum subsequently aged at 250F. Testing was conducted on 0.125 inch thick sheet. Quench-to-aging delay periods of 0 to 28 days, and initial artificial aging treatments at 212F for 24 and 48 hours were investigated. In addition, the effect of overaging T6 material at 320F for 13 hours was determined. The results of this investigation indicated that, for 7178 aluminum quenched sufficiently rapid from the solution treating temperature to prevent exfoliation in the T6 temper: 1) A quench-to-aging delay period of up to 28 days does not affect exfoliation characteristics when the alloy is subsequently aged at 250F for 24 hours. 2) Overaging beyond the T6 condition can produce susceptibility to exfoliation corrosion. 3) Underaging at 212F for 24 hours produces a high susceptibility to exfoliation corrosion. However, an additional heat treatment at 250F for as short a period as 8 hours will impart resistance to exfoliation. 4) Initial aging treatments at 212F for either 24 or 48 hours tend to reduce the maximum yield strength obtainable by a final heat treatment at 250F"--Abstract, page ii.


Sonnino, Carlo B., 1904-1998

Committee Member(s)

Frad, William A., 1909-1974
Sorrell, Charles A.


Materials Science and Engineering

Degree Name

M.S. in Metallurgical Engineering


University of Missouri--Rolla

Publication Date



vii, 63 pages

Note about bibliography

Includes bibliographical references (pages 118-119).


© 1969 J. James Slavick, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Aluminum -- Corrosion
Aluminum alloys -- Corrosion
Aluminum -- Heat treatment
Aluminum alloys -- Heat treatment
Metals -- Quenching

Thesis Number

T 2295

Print OCLC #


Electronic OCLC #


Included in

Metallurgy Commons