Masters Theses


Siyu Wei


”This work utilizes the Jominy End Quench Test and Plate End Quench Test to study the effect of quench rate on the microstructure and properties of Al-Zn-Mg-Cu commercial alloys (7040, 7050 and 7075). These properties include hardness, electrical conductivity, ductility, yield and ultimate tensile strengths.

SEM and FESEM were employed to examine the precipitation phenomena in 7XXX series aluminum alloys. Differential Scanning Calorimetry was also used to verify the precipitation sequence of these alloys. A finite element analysis of heat conduction process during quenching was performed. The chemistry, microstructures, and properties of 7040, 7050, and 7075 alloys were compared. The microhardness data of these alloys were fit into Avrami equations. The quench effect on the microstructure and properties of Al-Zn-Mg-Cu commercial alloys was studied.

It was found that 7040 is the least quench sensitive among the three Al-Zn-Mg-Cu alloys, while 7075 is the most quench sensitive. 7040 alloy showed an identical DSC thermogram at the fast quenched end and at the position 8~10mm away from it; 7050, on the other hand, demonstrated an apparent difference between these two positions. Hence, 7050 is more quench sensitive than 7040, although it is less quench sensitive than 7075. For all these alloys, hardness increases steadily with faster cooling, while electrical conductivity declines. For 7050 alloy, the tensile properties, including ultimate tensile strength, 0.2% yield strength, sharp notch strength, and elongation, increase with higher quench rate"--Abstract, page iii.


Newkirk, Joseph William

Committee Member(s)

Ramsay, Christopher W.
Rahaman, M. N., 1950-


Materials Science and Engineering

Degree Name

M.S. in Metallurgical Engineering


University of Missouri--Rolla

Publication Date

Spring 2002


x, 56 pages

Note about bibliography

Includes bibliographical references (pages 51-53).


© 2002 Siyu Wei, All rights reserved.

Document Type

Thesis - Restricted Access

File Type




Subject Headings

Alloys -- Quenching

Thesis Number

T 8024

Print OCLC #


Link to Catalog Record

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