Date of Award

Fall 1950

Degree Type

Thesis - Restricted

Degree Name

Master of Science (MS)



First Advisor

Schoen, J. E.

Second Advisor

Barkow, A. G.

Third Advisor

Greene, J. B.


Although numerous investigations have been made concerning the precipitation hardening of wrought aluminum alloys, little work has been done along those lines for the die-cast alloys. Because of the favorable combination of properties, low density, ease of casting, and the improvement of physical properties by the addition of alloying elements which render these alloys heat-treatable, there is increasing use of the economical die-casting methods in the mass production of parts made of these alloys today. An attempt was made during this investigation to develop a method to control the heat-treating processes of this Al-Si-Cu die-casting alloy. It was hoped that the correlation of metallography, physical testing, and X-ray diffraction analyses could be used to determine the optimum combination physical properties that would produce reproducible results. Unfortunately it was found early in the investigation that the techniques involved in these methods, particularly in regard to the time involved in their procedures, do not lend themselves to routine shop control. However, a desire to understand the precipitation hardening characteristics of this alloy and the need to discover the optimum conditions of solution and precipitation treatment which would give the best combination of properties, led to the continuation of the investigation of the physical properties, metallographic characteristics and X-ray diffraction analyses of this die-cast alloy and the changes brought about in this alloy by heat-treatment.