Fe-Mn-Si Shape Memory Alloy for Biodegradable Implants
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Solution Overview
Problem
Current biodegradable materials for medical implants, such as thermoplastic polymers and Mg-based alloys, face limitations in strength, elastic modulus, and stability, which hinder their use in load-bearing applications due to high elastic modulus and undesirable degradation characteristics like hydrogen gas release.
Innovation Solution
Development of a biodegradable Fe-Mn-Si shape memory alloy suitable for additive manufacturing, allowing tuning of elemental composition, elastic modulus, and biodegradation profile through processing parameters and post-processing steps, enabling the production of implants with tailored properties for various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermoplastic polymers are used as biodegradable materials, then biodegradability is improved, but strength and elastic modulus are insufficient for load-bearing applications
Solution Approach 1:
The invention uses Fe-Mn-Si alloy as a metallic biodegradable material that combines the benefits of biodegradability with high strength and appropriate elastic modulus, effectively replacing the inadequate thermoplastic polymer materials in load-bearing applications
2Strength
If Mg-based biodegradable alloys are used, then strength deficiencies are addressed, but hydrogen gas release during degradation limits their application
Solution Approach 1:
The Fe-Mn-Si alloy provides a biodegradable solution that avoids the harmful hydrogen gas release issue of Mg-based alloys, maintaining strength while eliminating the harmful degradation byproduct that limits Mg alloy applications
3Strength
If conventional metals with high elastic modulus are used, then strength is sufficient, but stress shielding problems occur when coupled with bone
Solution Approach 1:
The Fe-Mn-Si alloy's elastic modulus can be tuned through composition adjustments to match bone's mechanical properties, reducing the elastic modulus from conventional metal levels to a range that minimizes stress shielding while maintaining sufficient strength
4Adaptability or versatility
If Ni-based shape memory alloys are used, then shape memory capability is achieved, but cost and manufacturing complexity increase
Solution Approach 1:
The Fe-Mn-Si alloy replaces expensive Ni-based shape memory alloys with a cheaper iron-based composition, maintaining shape memory functionality while significantly reducing material cost and simplifying manufacturing processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The Fe-Mn-Si alloy provides a cost-effective, shape memory capability with tunable properties, enhancing biodegradability and mechanical performance, suitable for medical implants and other applications, while maintaining stability and reducing stress shielding issues.
Implementation Method 1
Shape memory materials have the ability to 'remember' and recover their original shape after a significant and seemingly plastic deformation or after cooling then heating or other external stimuli
Implementation Method 2
biodegradable materials are generally absorbed, hydrolysed or otherwise degraded within the body when allowed to do so
Implementation Method 3
when this alloy is used in a laser-based additive manufacturing process
Implementation Method 4
the properties of the fabricated product, such as, for example, the elemental composition, the elastic modulus, the biodegradability, and the strain recovery can be tuned by altering the processing parameters of the additive manufacturing process
Data Source
AI summary
The present invention is directed to a shape memory alloy, particularly a Fe-based shape memory alloy, that is suitable for use in additive manufacturing methods, as well as methods of use and methods of altering the composition of the alloy during fabrication.