Friction Stir Processing of Aluminum Plate End Faces Under Cooling
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Solution Overview
Problem
The end faces of age-hardening aluminum alloy plates used in armored vehicles are prone to delamination and cracking due to inhomogeneous microstructure and external loads, which existing surface welding methods cannot effectively prevent without significant material and labor costs.
Innovation Solution
A friction stir processing method is developed for the end surface of age-hardening aluminum alloy plates, involving butt-joining with a dissimilar plate, clamping, and performing friction stir processing underwater or in liquid nitrogen, followed by aging treatment to enhance interlayer bonding strength and prevent delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface welding method is used to prevent end surface cracking, then cracking resistance is improved, but material consumption and labor cost increase significantly
Solution Approach 1:
The patent replaces the welding process with friction stir processing, which uses mechanical friction and stirring to achieve material bonding and microstructure optimization without the need for extensive welding materials and post-weld treatments, thereby reducing material consumption while maintaining cracking resistance
Solution Approach 2:
The patent changes the processing parameters by using friction stir processing instead of welding, altering the fundamental mechanism from thermal joining to mechanical-microstructural modification, which eliminates the need for additional welding materials and reduces overall material consumption
2Reliability
If surface welding method is used to prevent end surface cracking, then cracking resistance is improved, but labor cost and processing time increase
Solution Approach 1:
The patent replaces the multi-step welding process with a single friction stir processing operation, eliminating the need for separate welding, cleaning, and post-treatment steps, thereby significantly reducing processing time while maintaining effective cracking prevention
Solution Approach 2:
The patent combines multiple functions (cracking prevention, surface treatment, and microstructure optimization) into a single friction stir processing operation, eliminating the need for separate welding and post-treatment steps, thereby reducing overall processing time
3Productivity
If friction stir processing is performed without cooling, then processing speed is improved, but thermal distortion and microstructure quality deteriorate
Solution Approach 1:
The patent introduces water or liquid nitrogen as a cooling intermediary during friction stir processing, which absorbs excess heat without interfering with the mechanical stirring action, thereby maintaining both high processing speed and superior microstructure quality through effective thermal management
Solution Approach 2:
The patent utilizes the phase transition properties of liquid nitrogen (from liquid to gas) as a cooling medium, which absorbs large amounts of heat during evaporation, effectively controlling thermal distortion while maintaining processing speed and ensuring high microstructure 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 method effectively prevents delamination and cracking of the end faces by improving interlayer bonding strength and enhancing the hardness and ballistic resistance of the stirring zone, while being more efficient and cost-effective than traditional welding methods.
Implementation Method 1
friction stir processing
Implementation Method 2
plastic flow in the thickness direction
Implementation Method 3
underwater condition or a liquid nitrogen cooling condition
Implementation Method 4
liquid nitrogen cooling condition
Implementation Method 5
performing aging treatment on the age-hardening aluminum alloy plate
Data Source
AI summary
A method for friction stir processing of an end surface of an age-hardening aluminum alloy plate is provided, in which a solid-solution state age-hardening aluminum alloy plate is butt-joined to and clamped with a dissimilar plate to obtain a combined plate; two sides of the combined plate are respectively provided with a weld-start plate and a lead-out plate; a bottom end of a stirring head is provided with a stirring pin; a distance between the outer edge of the stirring pin and the end surface of the age-hardening aluminum alloy plate is maintained to be 0.01-5 mm; the stirring pin is rotated into the weld-start plate; the age-hardening aluminum alloy plate is subjected to friction stir processing underwater or in a liquid nitrogen cooling condition; and the processed age-hardening aluminum alloy plate is separated and subjected to aging treatment.