Additive Manufacturing Ultrasonic Vibration Grain Refinement
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Solution Overview
Problem
Aerospace materials, such as Ti-6Al-4V and 300M alloy steel, face challenges in achieving superior specific strength and fatigue properties under multiaxial fatigue conditions, particularly in landing gear applications, due to their grain structure.
Innovation Solution
The method involves using additive manufacturing with a pulsed laser and high-frequency ultrasonic vibrations to create fine equiaxed grains with random crystallographic texture in aerospace materials, thereby refining the grain structure and improving mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional additive manufacturing is used to produce aerospace materials, then the manufacturing process can be completed, but the grain structure becomes coarse leading to reduced strength and fatigue properties
Solution Approach 1:
The patent applies ultrasonic vibration to the base material during laser additive manufacturing. The vibration mechanism generates high-frequency mechanical vibrations that interact with the molten material, preventing dendritic growth and promoting formation of fine equiaxed grains with random crystallographic texture, thereby resolving the contradiction between maintaining manufacturing feasibility and achieving fine grain structure for improved strength and fatigue properties
Solution Approach 2:
The patent modifies the thermal and mechanical parameters during the additive manufacturing process by introducing controlled vibrations and adjusting laser parameters. This changes the solidification conditions from conventional slow cooling to vibration-assisted rapid solidification, transforming the grain structure from coarse columnar to fine equiaxed grains, thus improving strength and fatigue properties while maintaining the additive manufacturing process
2Strength
If finer grain structures are created to improve strength, then the mechanical properties improve, but the manufacturing process complexity increases
Solution Approach 1:
The patent introduces a vibration mechanism that can be integrated into existing additive manufacturing systems. The ultrasonic vibration device adds minimal complexity to the conventional laser-based process while effectively refining the grain structure. The vibration is applied during the layer-by-layer construction process, enabling fine grain formation without requiring complete process redesign, thus improving specific strength with moderate increase in device complexity
Solution Approach 2:
The vibration mechanism serves multiple functions: it refines grain structure, controls solidification morphology, and promotes random crystallographic texture formation. By using a single vibration mechanism to achieve multiple microstructural benefits, the patent reduces the need for multiple separate process modifications, thereby limiting the increase in overall process complexity while achieving superior mechanical properties
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 results in ultra-fine-grained materials with enhanced strength and fatigue resistance, suitable for high-performance aerospace components, including landing gear, by reducing grain size and improving grain morphology.
Implementation Method 1
commanding, by a controller, a laser device to produce a plurality of optical pulses to a base material to add an additive material to the base material
Implementation Method 2
commanding, by the controller, a vibration mechanism to vibrate the base material as the plurality of optical pulses are being applied to the base material forming fine equiaxed grains with random crystallographic texture
Data Source
AI summary
A method is provided for producing ultra-fine-grained materials using additive manufacturing. The method includes commanding, by a controller, a laser device to produce a plurality of optical pulses to a base material to add an additive material to the base material. The method further includes commanding, by the controller, a vibration mechanism to vibrate the base material as the plurality of optical pulses are being applied to the base material forming fine equiaxed grains with random crystallographic texture in the base material.