Semi-Solid Metal Additive Manufacturing for Full-Density Parts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing metal additive manufacturing technologies face issues with poor uniformity and stability of component structure and performance due to non-equilibrium thermophysical processes, leading to defects like pores, shrinkage holes, and incomplete fusion, which are difficult to fully address with current methods that require special equipment and additional processes.
Innovation Solution
Applying strong mechanical forces during the solidification process of semi-solid metal to change dendrite growth to equiaxed crystal fine grain growth, eliminating shrinkage and pores, and improving stress distribution through a mold-free semi-solid rheoforming process using rotating and thrusting consumable materials with high-energy beam heating and external fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional metal additive manufacturing processes are used, then components can be manufactured with complex geometries, but the component structure and performance show poor uniformity and stability due to non-equilibrium thermophysical processes
Solution Approach 1:
The patent changes the thermodynamic state parameter of metal materials from solid to semi-solid state, and controls the phase composition ratio (liquid phase 10-30%, solid phase 70-90%) to achieve equiaxed crystal fine grain structure. This parameter change resolves the contradiction by enabling both complex geometry manufacturing and improved structural uniformity through rheological processing characteristics.
Solution Approach 2:
The patent applies strong mechanical force and vibration during the solidification process to change the traditional dendrite growth mode to equiaxed crystal fine grain growth mode. The mechanical vibration breaks the non-equilibrium solidification process, promoting uniform grain distribution while maintaining the ability to form complex geometries through controlled deposition.
2Ease of manufacture
If traditional additive manufacturing processes are used, then manufacturing can proceed with standard equipment, but serious deformation and cracking tendency occurs due to poor stress distribution
Solution Approach 1:
The patent changes the material state from solid to semi-solid with specific phase composition, which fundamentally alters the stress distribution characteristics during manufacturing. The semi-solid state with 10-30% liquid phase and 70-90% solid phase provides both ease of forming and improved stress distribution, reducing deformation and cracking tendency while maintaining manufacturing simplicity.
Solution Approach 2:
The patent applies strong mechanical force and vibration during solidification to improve stress distribution state of the formed body. This mechanical intervention prevents stress concentration that leads to cracking and deformation, while the process remains integrated into the additive manufacturing workflow without requiring separate stress relief operations.
3Reliability
If post-densification methods like hot isostatic pressing are used, then pore defects can be reduced, but special equipment and additional processes are required, affecting processing efficiency and increasing costs
Solution Approach 1:
The patent performs pore elimination action during the manufacturing process itself rather than as a subsequent operation. By applying strong mechanical force and vibration during solidification in the semi-solid state, pores and shrinkage holes are eliminated in real-time, achieving full density without requiring post-densification equipment like hot isostatic pressing, thus maintaining high processing efficiency.
Solution Approach 2:
The patent merges the densification function into the additive manufacturing process by combining material deposition, solidification, and pore elimination into a single integrated process. The semi-solid rheological processing simultaneously achieves shaping and densification, eliminating the need for separate post-densification operations and special equipment.
4Stability of the object's composition
If heat treatment and preheating methods are used to control microstructural morphology, then microstructure can be improved, but additional processes and special equipment are required, increasing complexity and cost
Solution Approach 1:
The patent performs microstructural control action during the manufacturing process by applying strong mechanical force and vibration during solidification in the semi-solid state. This preliminary action creates equiaxed crystal fine grain structure directly during deposition, eliminating the need for subsequent heat treatment processes and associated equipment, thus reducing device complexity while maintaining microstructural control.
Solution Approach 2:
The patent changes the material state to semi-solid with controlled phase composition (10-30% liquid, 70-90% solid) and applies mechanical vibration during solidification, which fundamentally alters the microstructural formation mechanism. This parameter change enables direct control of microstructural morphology during manufacturing without requiring additional heat treatment equipment or 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 method achieves full density and reduced deformation and cracking in additive parts, enhancing material purity and dimensional accuracy, allowing for near-net forming without special support structures and achieving mechanical properties comparable to forgings.
Implementation Method 1
the heat source is used to heat the front end surface of the consumables to a liquid or semi-solid state; the heat source comprises a laser beam
Implementation Method 2
the heat source comprises a laser beam, an electron beam, a plasma beam, an electric arc
Implementation Method 3
the heat source comprises a laser beam, an electron beam, a plasma beam, an electric arc, a resistance heat
Implementation Method 4
the rotational torsion and the axial thrust applied on the consumables have powerful effects such as shearing, agitation and extrusion
Implementation Method 5
the rotational torsion and the axial thrust applied on the consumables have powerful effects such as shearing, agitation and extrusion
Implementation Method 6
the hot metal at the end of these consumables undergoes agitation and extrusion under the action of the axial thrust, rotational torsion and the counter-acting force of substrate or stack layers, to form a mold-free semi-solid rheological processing metal structure
Implementation Method 7
the consumables are uniformly pushed forward at a consumption speed of 0.1-2 m/min and are moved at a speed of 0.1-4 m/min based on a moving path generated by the discrete sections to form continuous stack layers, and the stacking process is repeated to form a molded body
Data Source
AI summary
A micro-region semi-solid additive manufacturing method is provided, where rod-shaped materials are used as consumables, and front ends of the consumables are heated by means of high-energy beam, an electric arc, a resistance heat, or the like, to enable the front ends to be in a semi-solid state in which the solid-liquid two phases coexist; at the same time, the rotational torsion and the axial thrust are applied to the consumables to perform shearing, agitation and extrusion on the semi-solid front ends, that is, the mold-free semi-solid rheoforming is performed. The consumable is transmitted to the bottom layer metal continuously in this manner to form metallurgical bonding, the stacking process is repeated according to a planned route obtained after discretization slicing treatment, and then an object or a stack layer in a special shape can be formed.