The Flow Stress of AM IN 625 under Conditions of High Strain and Strain Rate
Additively manufactured (AM) nickel superalloy (In 625) with known processing history and quasi-static properties has been investigated under extreme strains up to about 100% and strain rate up to about 104/s by machining. A model for the calculation of the component of force that is due to indentation by the tool cutting edge was utilized to correct the measured shear force and material flow stress. The results are compared to flow stress measurements produced by Kolsky compression testing under strains of about 25% and strain rate of about 103/s. The highly instrumented setups utilized for the machining testing made possible an accurate description of the strain and strain rate at the primary shear zone (PSZ), and the temperature at the tool rake face that prevailed throughout the machining. The strain and strain rate were determined by digital image correlation. The temperature was determined by through-the-tool thermography. Differences observable during the cutting and dynamic compression of additive and wrought In 625 are outlined.
KeywordsAdditive manufacturing Machining Kolsky compression High strain rate High strain High temperature
This material is based upon work supported by the Department of Energy, National Nuclear Security Administration under Award Number DE-NA0003222. The authors wish to extend special thanks to Dr. Alkan Donmez from the National Institute of Standards and Technology for providing the additive In 625 that was tested; and to Dr. Steven Mates from the National Institute of Standards and Technology for providing the results from dynamic compression.
This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
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