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MATERIALS ENGINEERING

SEMINAR

“Investment Casting of Thin Sections in Superalloys”

By

Logan P. Kroneman

Purdue MSE Ph.D. Final Exam

Advisors: Professor Kevin P. Trumble and Professor Matthew J. M. Krane

ABSTRACT

When attempting to cast fine features, sharp corners can often become rounded as a result of the inability of the liquid metal to completely fill the mold. This inability to fill can be related to the wetting characteristics of the system, which are influenced by the composition and roughness of the mold wall. By better understanding how the liquid-mold interactions affect the ability to fill, a mold system can be designed to improve the precision of the as-cast shape.

A 2D, analytical model was developed to predict the ability to fill a V-shaped channel lined with circular particles. The model was found to accurately predict the ability to fill a channel. The head height and contact angle were found to have the biggest impact on the ability to fill. Sessile drop experiments with pure nickel droplets and alumina substrates of varying roughness found that the measured, or effective, The 2D analytical model was used to design a test casting to measure the ability to fill fine features similar to those in turbine blades as a function of head height, feature size, and corner angle. The wax pattern and empty mold were found to have to dependence on head height, as expected. The casting shows a linear dependence of ability to fill on head height. Using the head heights from the features of the casting, the predictions of the analytical model were found to show good agreement with the measured corners.

Date: Thursday, March 29, 2018

Time: 10:30 A.M.

Place: ARMS 1028