Application of multiple residual stress determination methods to coarse-grained biomedical implant castings

ABSTRACT

ASTM F75 femoral knee implant components distort during manufacture due to residual stress re-distribution or inducement. X-ray diffraction, neutron diffraction, centre-hole drilling and the contour method residual stress determination techniques were applied to as-cast and/or shot-blasted components. The centre-hole drilling and contour methods can only be considered qualitative as a result of uncertainty associated with the elastic anisotropy of gauge volumes. Additionally, neutron diffraction experimentation returned unfeasible results. However, it was qualitatively identified that a shot-blasting shell-removal process has the ability to significantly alter the bulk residual stress state of the implants and induce a stress state which would cause distortion by re-distribution following material removal during manufacturing processes.

KEYWORDS:

• Neutron diffraction
• X-ray diffraction
• contour method
• centre-hole drilling
• nano-indentation
• residual stress
• shot-peening
• shot-blasting
• CoCrMo
• ASTM F75
• femoral knee implants
• biomedical implants
• investment casting

Acknowledgements

The authors would also like to acknowledge the following personnel, universities and companies for conducting residual stress determination measurements and/or providing technical consultation: Dr Mike Woodard and Mr Yoshi Teramoto at Pulstec Industrial Co. Ltd., 7000-35, Nakagawa, Hosoe-cho, Kita-ku, Hamamatsu-City, Shizuoka Pref., 431-1304, Japan. Dr Xavier Ficquet and Dr Ed Kingston at Veqter Ltd., Unit 8 Unicorn Business Park, Whitby Road, Brislington, Bristol, BS4 4EX, UK. Dr Mike Prime, Los Alamos National Laboratory, Los Alamos, NM 87545, USA. Dr Gary Schajer, The University of British Columbia, Department of Mechanical Engineering, Vancouver Campus, 2054-6250 Applied Science Lane, Vancouver, BC Canada V6T 1Z4.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Sanjooram Paddea http://orcid.org/0000-0001-5981-3987

David Tanner http://orcid.org/0000-0002-6945-2000

Additional information

Funding

The authors would like to acknowledge the following sources of funding: Irish Research Council for Science, Engineering and Technology, award number EPSPG/2012/357. DePuy Synthes (Ireland). MedCast, a Seventh Framework Programme funded project (Project reference number: 251269). Experiments at the ISIS Pulsed Neutron and Muon Source were supported by a beam-time allocation and travel expense funding from the Science and Technology Facilities Council.