Cold Spray Preform Recrystallization by Lateral Compression Heating
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Solution Overview
Problem
Existing methods for producing wrought structures from cold spray deposition face challenges such as thermal stresses, oxidation, and the formation of defects like large tunnel defects and gas pockets, while being energy-intensive and costly, particularly in processes like HIP.
Innovation Solution
A method involving simultaneous application of heat and lateral compressive load to a cold spray deposited preform, raising the temperature to between the recrystallization temperature and melting point, facilitating rapid recrystallization and densification without melting, using techniques like rapid heating and lateral rollers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cold spray methods are used to produce low porosity deposits, then particle consolidation is achieved, but thermal stresses cause cracking and separation due to heating requirements
Solution Approach 1:
The patent replaces conventional thermal heating methods with a mechanical field approach using high power ultrasound. The ultrasonic vibrations generate localized mechanical energy that consolidates particles and eliminates porosity without significant thermal input, thereby avoiding thermal stresses that cause cracking and separation in conventional cold spray processes
Solution Approach 2:
The patent fundamentally changes the energy input parameter from thermal (heating to 700-1100°C) to mechanical (ultrasonic vibrations at high power). This parameter change enables particle consolidation and porosity elimination through mechanical vibration and cavitation effects rather than thermal softening, thus preventing thermal stress-induced defects
2Manufacturing precision
If high power ultrasound is applied to consolidate particles, then porosity is eliminated and density is improved, but equipment complexity increases
Solution Approach 1:
The patent integrates the ultrasonic consolidation function into the existing cold spray deposition system. The high power ultrasound source is incorporated as part of the deposition apparatus, allowing the same equipment to perform both particle deposition and consolidation functions, thereby minimizing additional equipment complexity while achieving superior density
3Manufacturing precision
If HIP process is used to eliminate porosity and create wrought structure, then material density is improved, but energy consumption and cost increase significantly
Solution Approach 1:
The patent replaces the thermal-mechanical HIP process with a purely mechanical ultrasonic consolidation approach. Instead of heating materials to high temperatures (950°C) and applying sustained high pressure (100 MPa) for extended periods (4 hours), the patent uses high power ultrasound to achieve consolidation at lower temperatures and shorter times, dramatically reducing energy consumption
Solution Approach 2:
The patent achieves porosity elimination and density improvement in a much shorter time frame compared to HIP processing. The high power ultrasound enables rapid consolidation during or immediately after deposition, skipping the lengthy heating, holding, and cooling cycles required by conventional HIP 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
This process efficiently transforms cold spray deposited structures into wrought structures with uniform microstructure and high density, avoiding defects and reducing energy consumption, suitable for continuous production of materials like titanium alloys.
Implementation Method 1
The kinetic energy of the particles is utilised to achieve bonding through plastic deformation upon impact with the substrate
Implementation Method 2
applying heat and a compressive load simultaneously to an application area of a cold spray deposition preform... raises the temperature of the material of the preform in the application area to between the recrystallisation temperature and the melting point
Implementation Method 3
applying heat and a compressive load simultaneously to an application area of a cold spray deposition preform... wherein the compressive load is applied laterally to the application area
Data Source
AI summary
A process and apparatus of producing a product having a wrought structure. The process comprises the step of: applying heat and a compressive load simultaneously to an application area of a cold spray deposition preform to transform the comprising consolidated particle structure into a wrought structure, the compressive load being applied laterally to the application area. The application of compressive load and heat to the application area raises the temperature of the material of the preform in the application area to between the recrystallisation temperature and the melting point of the material.