Russian scientists have developed a new processing method for magnesium alloys that enables implants to retain their desired shape longer and dissolve evenly in the body. Researchers from the National University of Science and Technology MISIS (NUST MISIS) worked on the technology together with colleagues from Moscow Institute of Physics and Technology (MIPT) and the Institute of Strength Physics and Materials Science of the Siberian Branch of the RAS.
Traditionally used steel or titanium implants require repeated surgical intervention for removal after bone repair. To avoid this, magnesium alloys are considered as an alternative because they gradually dissolve in the body. However, their use has been limited by low corrosion resistance.
“The main disadvantage of bioresorbable magnesium alloys is that without special treatment they have low corrosion resistance,” explained one of the study’s authors, PhD Stanislav Chernyshikhin, Head of the Additive Manufacturing Laboratory at NUST MISIS. “The implant begins to dissolve even before the bone is fully repaired, and this can lead to complications and repeated surgery”.
During the research, scientists were able to select a heat treatment mode for a sample 3D-printed from WE43 magnesium alloy powder that makes the implant dissolve up to 1.5 times slower. Furthermore, the heat treatment improved the homogeneity of the structure and reduced the number of microdefects in the implant.
“We have for the first time in Russia demonstrated that the durability of a magnesium alloy sample printed on a 3D printer is decisively affected by the level of residual mechanical stresses,” said Veronika Utyaganova, a researcher at the NUST MISIS Additive Manufacturing Laboratory. This level can be adjusted using the preset heat treatment modes. Residual porosity and technological defects in alloys after 3D printing can be controlled by controlling the volumetric density of laser energy”.
