Aluminum Alloy Disk Substrate Composition for Flutter-Resistant Rigidity
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Solution Overview
Problem
Magnetic disks with reduced thickness and increased speed suffer from disk flutter due to low rigidity, leading to increased frequency of errors in head positioning, and existing solutions either require high accuracy components or fail to effectively reduce fluttering characteristics across all frequency ranges.
Innovation Solution
An aluminium alloy substrate with specific compositions of Fe, Mn, Si, Ni, Cr, Zr, and optional elements like Cu, Mg, Zn, Ti, B, and V, combined with controlled Young moduli and loss factors, is used to enhance the rigidity and fluttering characteristics of magnetic disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of the magnetic disk is reduced to increase storage capacity, then the storage density is improved, but the rigidity of the disk is reduced causing increased disk flutter
Solution Approach 1:
The patent changes the material parameters by specifying precise alloy compositions (Fe: 0.01-3.00%, Mn: 0.01-3.00%, Si: 0.01-18.00%, Ni: 0.01-8.00%, Cr: 0.01-3.00%, Zr: 0.01-3.00%) and controlling the Young's modulus to be 67 GPa or more, thereby achieving the required rigidity in thinner substrates
Solution Approach 2:
The patent uses composite alloying by combining multiple elements (Fe, Mn, Si, Ni, Cr, Zr) with aluminum to create a composite material system that provides enhanced rigidity and flutter resistance while maintaining thin substrate dimensions
2Speed
If the rotational speed of the magnetic disk is increased to improve data access speed, then the reading speed is improved, but the fluid force increases causing more severe disk flutter
Solution Approach 1:
The patent changes the mechanical parameters of the substrate by controlling the Young's modulus to be 67 GPa or more and specifying precise alloy compositions, thereby increasing the critical speed at which flutter occurs and allowing higher operational rotational speeds without excessive vibration
3Ease of manufacture
If conventional alloy compositions are used to maintain manufacturing compatibility, then the ease of manufacture is preserved, but the rigidity and fluttering characteristics are insufficient
Solution Approach 1:
The patent modifies the alloy composition parameters from conventional specifications by precisely controlling the content ranges of Fe, Mn, Si, Ni, Cr, and Zr elements, and by setting the Young's modulus to be 67 GPa or more, thereby achieving enhanced rigidity while maintaining compatibility with existing manufacturing processes such as casting, rolling, and plating
Data Source
AI summary
Provided is an aluminium alloy substrate for a magnetic disk, a method for fabricating the substrate, and a magnetic disk composed of the aluminium alloy substrate for a magnetic disk. The substrate contains an aluminium alloy composed of one or more elements selected from a group comprising 0.05 to 3.00 mass % (hereinafter abbreviated as “%”) of Fe, 0.05% to 3.00% of Mn, 0.05% to 18.00% of Si, 0.05% to 8.00% of Ni, 0.05% to 3.00% of Cr, and 0.05% to 3.00% of Zr, with a balance of Al and unavoidable impurities. The substrate has a Young modulus of 67 GPa or more in each of the 0° direction, 45° direction, and 90° direction relative to the rolling direction of the substrate.