Turning induced residual stresses in Ti-6Al-4V dual modular hip endoprostheses

• Published in: Machining science and technology Vol. 29; no. 1; pp. 1 - 15
• Main Authors: Denkena, Berend, Bergmann, Benjamin, Prasanthan, Vannila, Legutko, Beate
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 02.01.2025
• Subjects: Load-adapted manufacturing; modular hip endoprostheses; residual stresses; tapered junction
• ISSN: 1091-0344; 1532-2483
• DOI: 10.1080/10910344.2025.2456236

In order to improve patient care, it is necessary to increase the lifetime of double modular hip endoprostheses with tapered junctions. One approach to increasing the lifetime of components is to adjust the residual stress state to the load. Therefore, this study investigates the influence of process parameters and the effect of their interaction on the residual stresses of outer tapers manufactured of Ti-6Al-4V. Generally, compressive residual stresses are present after turning. The process parameters cutting speed and feed have an influence on the circumferential and axial residual stresses. The feed significantly influences the residual stresses in the axial direction, while cutting speed affects the residual stresses in the circumferential direction. The depth of cut has no significant effect on the residual stresses in either direction. With increasing cutting speed, the residual stress state in the circumferential direction is shifted toward tensile residual stresses. This can be explained by the decreasing mechanical load on the subsurface and the predominant influence of the thermal effect. In the axial direction, the compressive residual stresses increase with increasing feed. Due to the low thermal conductivity of titanium, the thermal influence presumably predominates in the near-surface area for the analyzed process parameters.