Industrial Consultancy & Sponsored Research (IC&SR) , IIT Madras
A Method for Producing High Performance Cryorolled Ultrafine Grained Bimetallic Composite Sheets
Categories for this Invention
Technology: Cryorolled Ultrafine Grained Bimetallic Composite Sheets
Category: Advanced materials
Industry: Electronic System & Design Manufacturing (ESDM)
Application: Electrical and Electronics Industries.
Market: The global market size of projected to grow from USD 6.67 billion in 2018 to USD 12.17 billion by 2027, at a CAGR of 6.92%.
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Problem Statement
- Bimetals, particularly Al/Cu bimetals, are widely used in various industries due to their hybrid properties. They are particularly popular in electrical components like cables and connectors.
- Traditional manufacturing methods like diffusion bonding, roll bonding, explosive welding, and ultrasonic welding are suitable for Al/Cu bimetallic joining. However, intermetallic formation in these processes can reduce electrical conductivity and properties.
- Roll bonding is the most popular technique for producing Al/Cu bimetallic sheets due to its ease of use and process flexibility.
- A new, technologically advanced manufacturing route is needed to achieve superior interface, ultra-high bond strength, and excellent mechanical properties.
Technology
METHOD:
- The method comprising partitioning at least one aluminium plate and at least one copper plate with predetermined thicknesses and machined to the desired size
- Subjecting the aluminium and copper plates to homogenization through a heat treatment process
- Subjecting the aluminium and copper plates to cryogenic-soaking process to for a predefined time period
- Subjecting the aluminium and copper plates to multi-pass cryorolling with thickness reduction to develop cryorolled aluminium and copper sheets
- Subjecting the cryorolled copper sheet to a short thermal treatment followed by water quenching
- Performing surface preparation on the cryorolled aluminium sheet and copper sheet involving at least one of drilling, degreasing, scratch brushing and riveting
- Subjecting surface prepared sheets to roll bonding with a thickness reduction to develop ultrafine grained aluminium/copper bimetallic sheets
- Subjecting the ultrafine grained aluminium/copper bimetallic sheets to asymmetrical rolling
- Subjecting the asymmetrically rolled ultrafine grained aluminium/copper bimetallic sheets to heat treatment for a short period of time to produce high performance cryorolled ultrafine grained bimetallic composite sheets
Key Features / Value Proposition
Temperature
- Cryorolling is performed at a very low of approximately minus (-) 196°C.
Soaking
- The aluminium and copper plates in liquid nitrogen for minimum 15 mins before each pass.
A 2-High rolling mill
- Approximately 125 mm roll diameters and the rolling is carried out at approximately 6 to 8 rpm.
Thickness reduction
- 80% during multi-pass cryorolling with an average grain size of approximately 1 µm
Short thermal treatment
- 250°C to 450°C for a time period of 5 to 15 minutes.
Roll bonding
- a thickness reduction range of approximately 55 to 60%.
Roll Spec
- Roller diameter 300 mm
- Rolling speed 4-6 rpm and
- Rolling load 30-45 tons
Speed ratio
- Approximately 1.1 to 1.5 on a 2-high rolling.
Bond strength
- Approximately 24 to 28 N/mm and
- Excellent strength-ductility synergy
- (tensile strength of approximately 200MPa and
- Total ductility of ( 35 to 40%) approximately .
Questions about this Technology?
Contact For Licensing
sm-marketing@imail.iitm.ac.in
ipoffice2@iitm.ac.in
Research Lab
Prof. Sushanta Kumar Panigrahi
Department of Mechanical Engineering.
Intellectual Property
- IITM IDF Ref. 2492
- Patent No: IN 528430
Technology Readiness Level
TRL-4
Experimentally validated in Lab;