Diffusion Hammer Welding Oxide-Dispersed Platinum Sheets
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for connecting oxide-dispersed precious metal sheets, such as those used in the glass industry, face challenges with inhomogeneities and reduced strength at high temperatures due to coagulation of dispersoids during welding, leading to weak welded seams and reduced service life, especially in longitudinal seams of cylindrical parts.
Innovation Solution
A process involving chamfering the edges of the metal sheets with specific angles and widths, followed by diffusion hammer welding without weld fillers, and subsequent heat treatment to enhance creep rupture strength, while maintaining uniformity and reducing production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fusion welding is used to join oxide-dispersed precious metal sheets, then the joining process is simple and fast, but the dispersoids coagulate and float in the melt leading to coarse-grained microstructure and reduced strength
Solution Approach 1:
The invention changes the fundamental parameter of the joining process from fusion welding to diffusion bonding. This involves controlling the bonding temperature to remain below the melting point of the base metal (typically 0.5-0.8 times the melting temperature in Kelvin), preventing dispersoid coagulation while still enabling atomic diffusion across the interface. The process parameters include temperature, time, and pressure control to achieve bonding without melting.
Solution Approach 2:
The invention exploits the phase transition boundary by operating just below the melting point threshold. By controlling the bonding temperature to stay in the solid state regime rather than allowing transition to liquid phase, the dispersoids remain distributed in the solid matrix and do not coagulate or float, thus maintaining the reinforced microstructure in the bonded region.
2Strength
If oxide dispersion strengthened alloys are used to increase high-temperature strength, then the material can withstand thermal and mechanical stresses, but the dispersoids coagulate during welding reducing the strengthening effect
Solution Approach 1:
The invention changes the thermal parameter from above-melting-point fusion welding to below-melting-point diffusion bonding. This parameter change prevents the thermal conditions that cause dispersoid coagulation while still providing sufficient thermal energy for atomic diffusion and bonding. The bonding temperature is carefully controlled to maintain dispersoid distribution integrity.
Solution Approach 2:
The invention converts the potential harm of high temperature (which causes dispersoid coagulation) into benefit by using controlled thermal diffusion. The heat treatment process, when properly controlled below melting point, promotes beneficial atomic diffusion for bonding while the low temperature regime prevents harmful dispersoid coagulation, thus converting thermal energy from a harmful to beneficial factor.
3Shape
If longitudinal welded seams are used in cylindrical structural parts, then the required geometry is achieved, but the seams are subjected to twice the acting stresses and often fail
Solution Approach 1:
The invention changes the bonding mechanism parameter from fusion-based to diffusion-based joining. This fundamental parameter change creates a bonded joint with microstructure and mechanical properties matching the base material, eliminating the weak seam characteristic of fusion welded joints that fail under the doubled longitudinal stresses in cylindrical components.
4Strength
If hammer welding is used to avoid fusion welding defects, then the dispersoids are not melted, but the process requires extreme preparation and control leading to high costs and labor
Solution Approach 1:
The invention replaces the complex mechanical hammer welding system with a controlled thermal diffusion process. Instead of using mechanical impact and extreme precision positioning, the diffusion bonding process uses controlled temperature and pressure fields that are easier to implement and control, reducing manufacturing complexity while achieving superior joints.
Solution Approach 2:
The invention changes the controlling parameters from mechanical (impact force, positioning precision) to thermal-field parameters (temperature, time, pressure). This parameter transformation simplifies the process control requirements and reduces the need for extreme preparation and real-time control, making the process more manufacturable while maintaining high joint quality.
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 significantly improves the creep rupture strength of the joined product, maintaining high mechanical and thermal resistance with reduced production expenditure and minimizing the risk of seam failure, achieving strengths comparable to unwelded starting materials.
Implementation Method 1
oxide dispersion strengthened platinum-base alloys are increasingly used, since these are characterized by a higher ability to withstand thermal, mechanical and chemical stresses than standard alloys. Oxide-dispersed alloys, also referred to as ODS alloys hereinbelow, are distinguished by a very homogeneous microstructure.
Implementation Method 2
the alloy is melted. Whereas only very minor losses in strength can be observed in the welded seam when melting classic substitutional solid solution alloys as result of recrystallization during use above 1200°C, the melting when welding oxide dispersion strengthened alloys leads to the coagulation and floating of a majority of the dispersoids
Implementation Method 3
the welding of the individual materials is respectively performed below their melting temperature, with at least partial formation of a diffusion bond in the joining region
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
The present invention relates to a process and a device for joining precious metal sheets (1,4) to form structural parts, and to the products (1,4) made by the process.