The close match between the elastic properties of an implant material and a human bone is crucial to avoid the stress-shielding effect. Therefore, low modulus biomaterials are desirable for the load-bearing biomedical implants to ensure rapid healing of the hard bone tissue. Due to its complex hierarchical structure, the bone tissue features moderate strength values similar to those of some metals while its elastic modulus is comparable to that of some polymers [1], [2]. Implant materials for the bone fixation should be several times stronger compared with that of the bone tissue. Metals – main candidates for the bone fixation – are typically too stiff because of the general trend between strength and elastic properties: a stronger material possesses a higher modulus of elasticity. In this work, we explore hierarchical metal-metal composite synthesized by laser powder bed fusion and liquid metal dealloying (LMD) to mimic the structure of bone tissue. The LMD is a metallurgical process of selective corrosion using metallic melt, which is used for the synthesis of bicontinuous nanomaterials and recycling of complex alloys. The mechanical behaviour of the hierarchical metal-metal composites was probed under the compression loading. It was found that their elastic modulus is close to that of the bone tissue. Microstructure of the composites before and after deformation was analysed by X-ray and electron microscopy. The results suggest that the developed hierarchical metal-metal composites mimicking the structure and the elastic behaviour of the bone tissue are technologically interesting for biomedical applications.

References

[1] I. V. Okulov et al., “Open porous dealloying-based biomaterials as a novel biomaterial platform,” Mater. Sci. Eng. C, vol. 88, no. August 2017, pp. 95–103, 2018, doi: 10.1016/j.msec.2018.03.008.First name initials, Last name; J.S. Smith Journal title, year, volume, page numbers.

[2] I. V. Okulov, J. Weissmüller, and J. Markmann, “Dealloying-based interpenetrating-phase nanocomposites matching the elastic behavior of human bone,” Sci. Rep., vol. 7, no. 1, 2017, doi: 10.1038/s41598-017-00048-4.