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The most common causes of conducting a hip revision surgery after total hip replacement are aseptic loosening (aseptic instability) of the endoprosthesis, bone destruction as a result of contact with the endoprosthesis, and a periprosthetic fracture. These are the effects of load transfer to the bone tissue in arthroplasty resulting due to the difference in stiffness of the endoprosthesis and the bone. Titanium alloy is widely used in endoprostheses manufacturing because of its high biocompatibility, good wear properties, and corrosion resistance, but such endoprostheses are stiffer than the femur. These problems have raised interest in searching for the best materials and topology for a femoral implant. Nowadays additive technology is of great interest as it enables to create materials with graded density. These materials consist of multiple lattice structures with variable parameters and topology. By varying the parameters of lattice structures one can adjust the mechanical properties of the material as required. These materials find their application in hip endoprostheses manufacturing, allowing to adjust the parameters of the lattice structures, and deliver a product with femur‐like mechanical properties. The porous structure also ensures bone tissue ingrowth into the prosthesis. The authors designed and simulated an endoprosthesis made of graded density lattice structures with femur‐like mechanical properties. Using a numerical simulation software Ansys Mechanical authors determined the effect of the topology on the structural behavior of the femur and defined the endoprosthesis‐femur combined performance under various load cases.

Additive manufacturing is considered to be a very promising technology when it comes to the manufacture of metal products of a complex shape for various applications, since it provides designs with improved mechanical properties. Another advantage of modern solutions for additive manufacturing is that they help manufacturers to control the in-process structure formation of final products. Of special interest is the feasibility of simultaneously creating local regions with preferred microstructures and properties. This paper discusses the effect of the process parameters of selective laser melting (SLM) on the structure and properties of Inconel 718 specimens. The results of uniaxial tension experiments on homogeneous specimens, as well as on structurally graded specimens with equiaxed fine grains and elongated coarse grains, are presented. The authors also proposed a finite-element approach to modeling of mechanical properties. The input data include experimental data describing tensile specimens manufactured using two different process regimes of SLM to obtain different types of microstructure (equiaxed fine-grained and coarse columnar-grained), as well as experimental data on tensile tests of the composite specimen. The proposed approach defines the spatial distribution of material properties in homogeneous and structurally graded specimens. This paper presents the results of modeling based on the proposed approach for the inelastic behavior of structurally graded specimens as compared to the experimental data.

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