Date of Award
Doctor of Philosophy (PhD)
Grujicic , Mica
Omar , Mohammad
Prucka , Robert
In metal injection molding (MIM), fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density.
The obstacle to sinter bonding a MIM part to a conventional (solid) substrate lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. It is also the reason, why sinter bonding MIM to solid substrates is not an industrially applied process and little to no prior research exists.
By applying a structure of micro features to the surface of the MIM part, this allows for shrinkage while bonding to the substrate. The micro features tolerate certain plastic deformation to permit the shrinkage and thermal expansion/contraction without causing cracks after the initial bonds are established. The bonding and deformation behavior of the powder compacts is analyzed and modeled. A new approach to simulate the deformation is developed. Finally, the samples are evaluated and compared with other joining processes.
Martens, Thomas, "MICRO FEATURE ENHANCED SINTER BONDING OF METAL INJECTION MOLDED (MIM) PARTS TO A SOLID SUBSTRATE" (2011). All Dissertations. 710.