Casting of Magnesium Foam for Bone Regrowth

Hannah Ullberg, “Casting of Magnesium Foam for Bone Regrowth”
Mentor: Pradeep Rohatgi, Materials Science & Engineering

Large-scale bone damage can be mended by bone replacements. The porosity of bone can be artificially reproduced with foam structures, which can then be placed in the body to form a scaffold for the bone cell growth. Magnesium (Mg) will degrade on account of corrosion due to the environmental conditions in the human body, thus the degradation of a magnesium foam leaves a newly grown bone. In this work, a low-cost pressure infiltration casting technique was developed which enables synthesis of magnesium foams which can be used as scaffolds. Foam and mold shapes were designed then 3D printed using PLA material, then covered in plaster to form the mold shape. After sintering, plaster molds were pressure infiltrated with AZ91E (Mg alloy) to form the magnesium foams, which have mechanical properties similar to human bone. Compression tests of the porous foams and the solid block exhibited improvement. Magnesium foams with porosity were compression tested and metallographically studied. These results show that a magnesium foam can be created with a controlled porosity viable for bone regrowth.

Comments

  1. Very good work, Hannah! This is very good research and you met the objectives of your research.

    You were clear in your speech and explained each aspect of the poster. Few things that could be improved would be your delivery. It seemed a little monotonous and at times I wasn’t sure which part you were explaining.

    One question I had about the work, is what do you learn from the simulation? You mentioned that there is minimal compression of the foam under 150 MPa load and that it mimics the bones. How much do bones compress under this load? How comparable are the results? Please let me know.

    Thank you for your time.

    1. Hello, I thank you for your feedback. In the time since you commented, a corrected version of the poster has replaced the version you saw.

      Literature states that the compressive strength of bone (cortical bone specifically) is 150MPa, so theoretically the bone does not compress under this load. Therefore, the simulation result of minimal deformation of the foam under the same load indicates that the Mg foam structure resembles the properties of bone.

      Another aspect learned from the simulation is the areas of stress concentration. This is a helpful property to understand when designing other foam structure shapes. Changing the shape changes the points of stress concentration, and simulations show these places. The shape can then be modified and optimized virtually before physical foams are created.

  2. Hello Hannah,

    Very fine work–congratulations! I think you presented your research very effectively; it was clear and concise, both the poster and the explanation. As a result, I found myself fascinated by the project. I concur with the other judge that strengthening your verbal presentation style will better engage your audience. I realize that presenting your research online is very different than engaging with your audience face-to-face, but when you present, keep in mind your own enthusiasm and curiosity that you invest in your research. Share that with your audience. Best wishes in your future work!

    1. Hello, I appreciate your feedback and will work towards a more engaging presentation style in the future.

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