Polished Titanium Alloy Timepiece Components With Fine-Grained Microstructure
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Solution Overview
Problem
Existing titanium alloys used in timepieces and jewelry suffer from poor polishability due to visible β phase grain microstructure and abrasive embedding, limiting their application to satin-finish or sand-blasted surfaces.
Innovation Solution
A thermomechanical treatment process involving heat treatment, deformation, and controlled precipitation of metastable ω phase and α phase to achieve a homogeneous and fine-grained microstructure suitable for polishing, using mechanical spectroscopy for temperature optimization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If titanium alloy is used for timepiece component, then density is reduced and mechanical properties are improved, but surface polishability deteriorates due to visible β phase grain microstructure
Solution Approach 1:
The invention changes the microstructural parameters of the titanium alloy through controlled heat treatment and deformation processes. Specifically, it transforms the β phase grain size and distribution by applying specific temperature ranges (700-900°C heat treatment) and deformation conditions, which modifies the microstructure to achieve a homogeneous fine-grained state that polishes well while maintaining the low density advantage of titanium alloy.
Solution Approach 2:
The invention creates a composite microstructure within the titanium alloy by controlling the precipitation and distribution of α phase within the β phase matrix. This dual-phase microstructure (α+β) with specific grain size distributions provides both the mechanical properties and surface polishability required, effectively combining the benefits of different phase characteristics within a single material system.
2Strength
If titanium alloy is used for timepiece component, then mechanical properties are improved, but surface defects increase due to abrasive embedding in β phase grains
Solution Approach 1:
The invention applies preliminary heat treatment and deformation actions before the final polishing stage. By pre-establishing a homogeneous fine-grained microstructure through controlled β phase grain refinement and α phase precipitation, the material becomes more resistant to abrasive embedding during subsequent polishing, preventing surface defects before they occur.
Solution Approach 2:
The invention modifies the physical parameters of the titanium alloy microstructure by controlling grain size, phase distribution, and hardness through heat treatment temperature and deformation degree. These parameter changes result in a microstructure where the hardened α phase precipitates within the β phase grains, creating a more uniform surface that resists abrasive embedding while maintaining mechanical strength.
3Object-generated harmful factors
If satin or sand-blasted finish is applied to prevent polishing defects, then surface appearance is improved, but surface appearance options are limited
Solution Approach 1:
Instead of applying surface treatments (satin or sand-blasted finishes) to mask polishing defects, the invention inverts the approach by modifying the bulk microstructure of the titanium alloy itself through heat treatment and deformation. This creates a material that can be polished to a high shine without defects, thereby enabling a wider range of surface appearances including high-polish finishes that were previously unattainable.
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
Enables high-quality polished surfaces with reduced roughness and hardness, overcoming the limitations of prior art by providing a polished finish compatible with timepiece and jewelry standards.
Implementation Method 1
a heat treatment, in a first time, of the titanium alloy at a temperature higher than the transition temperature Tβ from the α phase to the β phase followed by cooling
Implementation Method 2
a succession of cycles of deformation or at least one cycle of deformation
Implementation Method 3
nucleation or precipitation of a metastable w phase by heat treatment at low temperature followed by precipitation of an α phase by heat treatment at an intermediate temperature
Data Source
AI summary
The timepiece or jewellery component includes at least one part made of titanium alloy, one surface of which is polished. In some embodiments, the arithmetic mean roughness Ra of the polished surface can be less than 15 nm, even less than 12 nm, even less than 10 nm, and/or the mean total roughness Rz of the polished surface can be less than 90 nm, or even less than 80 nm, or even less than 60 nm. In some embodiments, the titanium alloy contains grains, notably β phase grains, and the difference between the mean height of the grains, notably of the β phase grains, of the polished titanium alloy surface is less than 150 nm, or even less than 120 nm, or even less than 100 nm.