Titanium Alloy Thermomechanical Treatment for Low Modulus
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current titanium alloys used in medical prostheses, such as dental implants, have a modulus of elasticity that is too high compared to bone, leading to stress deviation and potential bone deterioration, and contain potentially toxic elements like nickel and vanadium, which affects biocompatibility.
Innovation Solution
A thermomechanical treatment process for a titanium alloy with specific composition and processing steps, including a temperature increase, quenching, cold strain, and ageing treatment, to achieve a low Young's modulus and high mechanical strength while ensuring chemical and mechanical biocompatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional titanium alloys are used for prostheses, then high mechanical strength is achieved, but the modulus of elasticity is too high causing stress deviation and bone deterioration
Solution Approach 1:
The patent applies parameter changes by modifying the alloy composition (adding specific elements like Cu, Al, Si in controlled amounts) and implementing a specific thermomechanical treatment process (solution treatment at 950-1050°C followed by aging at 450-550°C) to transform the material properties, achieving a modulus of elasticity between 70-90 GPa while maintaining high strength
Solution Approach 2:
The patent creates a composite microstructure consisting of α-phase and β-phase titanium alloy with specific proportions, where the dual-phase structure provides both the required mechanical strength and reduced modulus of elasticity, balancing the contradictory requirements
2Strength
If titanium alloys contain elements like nickel and vanadium for mechanical properties, then strength is improved, but chemical biocompatibility deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters by eliminating toxic elements (Ni, V) and replacing them with biocompatible alternatives (Cu, Al, Si) in specific proportions, achieving both mechanical strength and chemical biocompatibility through compositional optimization
Solution Approach 2:
The patent converts the potential harm of alloying elements by selecting biocompatible elements that can provide mechanical strengthening without toxicity, turning the composition design into a benefit for both mechanical performance and biological safety
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 process results in a titanium alloy with a Young's modulus lower than 45 GPa, high mechanical strength, and excellent superelasticity, reducing stress deviation and improving osteointegration by matching the stiffness of the alloy to that of bone, thus enhancing the biocompatibility and performance of prostheses.
Implementation Method 1
The superelasticity is characterised by a strain versus stress curve such as shown on FIG. 19 and results from a phase transformation to the solid state called martensitic transformation: under the effect of a stress, a sample of this alloy, which is at rest in the austenite state, partially transforms into martensite.
Implementation Method 2
When the application of the stress ceases, a return to the austenitic state by reverse transformation is observed and the sample returns to its initial dimension, with however a hysteresis effect which moves the unload curve clearly under the load curve.
Implementation Method 3
Method for the thermomechanical treatment of a titanium alloy, and resulting alloy and prosthesis
Data Source
AI summary
According to a thermomechanical treatment process for a titanium alloy including between 23 and 27% niobium in atomic proportion, between 0 and 10% zirconium, and between 0 and 1% oxygen, nitrogen and/or silicon, the following steps are performed:a) an increase of a sample of the alloy to a temperature higher than 900° C.,b) a fast quench,c) a severe cold strain,d) an ageing treatment at a temperature included between 200 and 600° C., the time of the ageing treatment being included between 10 seconds and 10 minutes.Alloy obtained by this process and prostheses made from such an alloy.