Masters Theses

Keywords and Phrases

Fibrous monolith


"In an effort to improve the performance of petroleum drill bits produced by Smith Bits (a division of Smith International, Inc., Houston, TX), a series of cemented carbide materials with an engineered architecture were developed. This engineered architecture is comprised of a brittle wear resistant WC-Co cell surrounded by a ductile cobalt cell boundary. This structure is meant to mitigate catastrophic failure of the cemented carbide inserts on petroleum drill bits. In a lab it is difficult to simulate the conditions of drilling in the earth, thus several tests were employed to characterize the mechanical and wear behavior of the materials and determine their viability for use in the petroleum drilling industry. The tests utilized in this study were transverse rupture strength (TRS), fracture toughness using a chevron notched beam, high stress wear resistance (ASTM B611), and low stress wear resistance (ASTM G65). The strength results were examined, and with the aid of object oriented finite element (OOF) analysis, the strength was determined to be controlled by the tensile weakened cobalt cell boundary. The composites exhibited equivalent or higher fracture toughness over monolithic cemented carbides with equivalent cobalt content when tested in certain orientations. The wear resistance of the composite materials was improved over monolithic cemented carbides with equivalent quantities of cobalt"--Abstract, page iv.


Hilmas, Greg

Committee Member(s)

Fahrenholtz, William
Newkirk, Joseph William


Materials Science and Engineering

Degree Name

M.S. in Ceramic Engineering


University of Missouri--Rolla

Publication Date

Fall 2004

Journal article titles appearing in thesis/dissertation

  • Functionally designed cemented carbides
  • Wear characteristics of functionally designed cellular Cemented carbides produced by coextrusion
  • Strength of functionally designed cellular cemented carbides produced by coextrusion


xiv, 141 pages

Note about bibliography

Includes bibliographical references.


© 2004 Sean E. Landwehr, All rights reserved.

Document Type

Thesis - Restricted Access

File Type




Subject Headings

Tungsten carbide-cobalt alloys
Thermal stresses

Thesis Number

T 8701

Print OCLC #


Electronic OCLC #


Link to Catalog Record

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