Development and evaluation of P/M processing techniques to improve and control the mechanical properties of metal injection molded parts

Author

J. Alan Sago

Abstract

"Metal Injection Molding (MIM) is one of the most rapidly growing areas of powder metallurgy (P/M) but the growth ofMIM into new markets and more demanding applications is limited by two fundamental barriers, the availability of low cost metal powders and a lack of knowledge and understanding of how mechanical properties, especially toughness, are affected by the many parameters in the MIM process. The goals of this study were to investigate solutions to these challenges for MIM.

Mechanical alloying (MA) is a technique which can produce a wide variety of powder compositions in a size range suited to MIM and in smaller batches. However MA typically suffers from low production volumes and long milling times. This study will show that a saucer mill can produce sizable volumes of MA powders in times typically less than an hour. The MA process was also used to produce powders of 17-4PH stainless steel and the NiTi shape memory alloy for a MIM feedstock. This study shows that the MA powder characteristics led to successful MIM processing of parts.

Previous studies have shown that the toughness of individual MIM parts can vary widely within a single production run and from one producer to another. In the last part of the study a Design of Experiments (DOE) approach was used to evaluate the effects of MIM processing parameters on the mechanical properties. Analysis of Variance produced mathematical models for Charpy impact toughness, hardness, density, and carbon content. Tensile properties did not produce a good model due to processing problems. The models and recommendations for improving both toughness and reproducibility of toughness are presented"-- Abstract, p. iv

Advisor(s)

Newkirk, Joseph William

Committee Member(s)

Kohser, Ronald A.
Ramsay, Christopher W.
Peaslee, Kent D., 1956-2013
Dogan, Fatih

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Metallurgical Engineering

Comments

A portion of this study was supported by a grant from the Missouri Research Board.

Publisher

University of Missouri--Rolla

Publication Date

Summer 2004

Journal article titles appearing in thesis/dissertation

• Evaluation of metal injection molding processing of mechanically alloyed powders
• The effects of processing control parameters on the mechanical properties of metal injection molded parts

Pagination

xiii, 135 pages

Note about bibliography

Includes bibliographical references (pages 130-134)

Rights

© 2004 James Alan Sago, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Subject Headings

Powder metallurgy
Injection molding of metals
Notched bar testing

Thesis Number

T 8558

Print OCLC #

62206173

Recommended Citation

Sago, J. Alan, "Development and evaluation of P/M processing techniques to improve and control the mechanical properties of metal injection molded parts" (2004). Doctoral Dissertations. 1588.
https://scholarsmine.mst.edu/doctoral_dissertations/1588