Effect of Post-Processing on the Properties of MIM8740


AISI 8740 is increasingly being used as a material of choice for metal injection molding due to its combination of strength and toughness. Hot Isostatic Pressing of parts previously fabricated by metal injection molding has been shown to result in sizable property improvements. While HIP is known to improve properties by achieving full density, the already high density produced by MIM usually leads to only modest gains from HIP. An investigation into the effect of HIP on the MIM8740 was carried out. MPIF standard Charpy impact toughness samples and tensile samples were tested to document the property improvements. Microstructural analysis was used to determine the mechanism for the larger than expected property improvement. The properties achieved were very good and compare favorably with other available materials. Reduction in porosity during the HIP treatment was the major factor in determining the mechanical property improvements. However, grain growth during the HIP treatment reduced the potential gains from this treatment. It may be possible to design better processing routes that would increase the mechanical properties as well as lower the cost of the treatments. Appropriate tempering schedules could be designed to provide a range of mechanical properties combinations.

Meeting Name

2012 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2012 (2012: Jun. 10-13, Nashville, TN)


Materials Science and Engineering

Keywords and Phrases

Charpy Impact Toughness; Mechanical Property Improvement; Metal Injection Molding; Microstructural Analysis; Post Processing; Processing Route; Property Improvement; Strength and Toughness; Grain Growth; Hot Isostatic Pressing; Powder Metallurgy; Strength of Materials

International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


File Type





© 2012 Metal Powder Industries Federation, All rights reserved.

Publication Date

01 Jun 2012

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