Impact Weld Additive Manufacturing for Crack-Resistant Dissimilar Metals
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Solution Overview
Problem
Current additive manufacturing methods, particularly for dissimilar metals like aluminum to steel and nickel-based superalloys, face challenges such as precipitation of brittle phases, segregation, liquation cracking, and strain age cracking due to high heat input in fusion techniques, which are undesirable for turbine components.
Innovation Solution
The method employs impact welding using a discharge actuated arrangement, where metallic material is propelled at high velocity to form an impact weld on a substrate, avoiding high heat input by using magnetic pulse welding, laser impact welding, vaporized foil actuator welding, or discharge actuated welding, allowing for solid state additive manufacturing with minimal melting and reduced residual stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If high heat input fusion techniques (arc welding, laser welding) are used for additive manufacturing, then deposition capability is improved, but precipitation of brittle phases, segregation formation, and liquation cracking occur
Solution Approach 1:
The patent changes the fundamental parameter of welding temperature from above-melting-point (fusion) to below-melting-point (solid state). This parameter change eliminates the solidification process that causes cracking while maintaining deposition capability through plastic deformation and diffusion bonding at elevated temperatures.
Solution Approach 2:
The patent replaces the thermal-melting mechanism with a mechanical-impact mechanism. Kinetic energy from propelled wire or powder is converted to deformation energy upon impact with the substrate, achieving metallurgical bonding without melting. This substitution eliminates heat-related defects while maintaining deposition capability.
2Reliability
If solid state welding is used to avoid high heat input, then cracking and segregation are avoided, but productivity is reduced
Solution Approach 1:
The patent employs periodic impact welding where wire or powder is propelled in discrete pulses toward the substrate. Each pulse creates an impact weld, and by controlling pulse frequency and overlap, high deposition rates are achieved while maintaining solid state bonding conditions that prevent cracking.
Solution Approach 2:
The patent performs preliminary heating of the substrate and/or material to elevated temperatures (below melting point) before impact. This pre-heating reduces the thermal gradient during impact welding, enhances diffusion bonding, and allows higher deposition rates without causing cracking.
3Temperature
If conventional solid state additive manufacturing (binder jetting, sheet lamination) is used, then high heat input is avoided, but the processes are slow and limited to specific materials
Solution Approach 1:
The patent changes the material state parameter from room temperature (conventional solid state) to elevated temperature (below melting point). This temperature change enables direct metallic bonding with high strength properties while maintaining the low heat input advantage, achieving both high productivity and material versatility.
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 approach enables efficient and productive solid state additive manufacturing with reduced cracking and residual stresses, suitable for high-temperature components like turbine parts, improving productivity and avoiding the limitations of traditional high heat input processes.
Implementation Method 1
Metallic shot material is loaded into a magazine of the discharge actuated device. The metallic material is then discharged from the device through the opening wherein the discharged metallic particle is propelled toward a substrate of sufficient velocity to form an impact weld
Implementation Method 2
The metallic material is propelled toward the substrate with sufficient velocity to form an impact weld of the metallic material to the substrate
Data Source
AI summary
A method for forming an impact weld used in an additive manufacturing process is provided. The method includes providing a metallic material for impact welding to a substrate. The metallic material is propelled toward the substrate with a sufficient velocity to form an impact weld for welding the metallic material to the substrate. Further, the method includes traversing the substrate in a direction relative to a direction from which the metallic material is propelled and repeating the propelling so that a layer of additive material is deposited on the substrate as desired. In addition, a method for forming an impact welding used in an additive manufacturing process via discharge actuated arrangement is provided.