CANMET- MTL May 11, 2011 Hamilton, Ontario, Canada Grain Refinement of Magnesium Alloys Grain Refinement of Magnesium Alloys by CONFORM: A Continuous Severe by CONFORM: A Continuous Severe Plastic Deformation Route? Plastic Deformation Route? Youliang He Jian Li Robert Eagleson CANMET-MTL, Natural Resources Canada Youliang He , Jian Li, Robert Eagleson, Pei Liu, Ruby Zhang Fei Gao, Baoyun Song, Rong Fu, Guiming Wu Dalian Jiaotong University P R China Dalian Jiaotong University , P . R. China Lan Jiang McGill University
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CANMET-MTL
May 11, 2011Hamilton, Ontario, Canada
Grain Refinement of Magnesium Alloys Grain Refinement of Magnesium Alloys by CONFORM: A Continuous Severe by CONFORM: A Continuous Severe
Youliang He, Jian Li, Robert Eagleson, Pei Liu, Ruby Zhang
Fei Gao, Baoyun Song, Rong Fu, Guiming WuDalian Jiaotong University P R ChinaDalian Jiaotong University, P. R. China
Lan JiangMcGill University
CANMET-MTL
What is Severe Plastic Deformation? Why SPD?
• Large Deformation Strain: > 3• No Dimension Change After Deformation • Normally a Repeatable Process• Normally a Repeatable Process• No Fracture or Damage to the Workpiece• Batch & Continuous Modes
Fabricate Ultrafine or Nano-Structured Bulk Metallic Materials.
Achieve Favourable Properties: High Strength at Room Temperature and/or Superplasticity at Moderate Temperatures and High Strain Rates.
Severe Plastic Deformation: ECAP + Continuous Feeding
RollerZhang et al 2006
Shoe
Feed stock
RollerZhang et al., 2006
Wheel
AbutmentAbutment
ECAP with Continuous
Feeding
ECAP C f
• Large Shear Strain
ECAP-Conform
Zhu et al., 2006
CONFORM
Large Shear Strain• Hydrostatic Pressure
Srinivasan et al., 2006
CANMET-MTL
Continuous Extrusion Forming: A Combined Deformation Process
Roller Wheel Shoe
AsymmetricRolling Cu
Shear
ECAP Al
Abutment
Extrusion
Friction force as driving Invented in UK Maximum Extrusion
Materials:
Friction force as driving force: low energy consumption
High production rate Continuous production
Invented in UKAtomic Energy Authority in 1970’s
Maximum Extrusion Width: Al ~130 mm, Cu ~320 mm Maximum Product Area: Al ~13000 mm2Materials:
Al, Cu, Pb, Zn, Mg Continuous production Low scrap levels
Al ~13000 mmCu ~6400 mm2
CANMET-MTL
CONFORM: A Continuous Severe Plastic Deformation Route?
T. Erlien et al, NANOSPD3, 2005
Higher Effective Strain than ECAP C ti O ti
CONFORM ECAP
Continuous Operation Already Commercialized Various Product Shapes
Not Widely Recognized YetMore Research NeededMore Research Needed
CANMET-MTL Application to Magnesium Alloys (AZ31)
8 mm
Extruded Cast
Feedstock Cast Microstructure
Both cast and extruded rods can be used as feedstock
CONFORM Machine
Both cast and extruded rods can be used as feedstockHeating of the feedstock and the die chamber neededOne pass CONFORM extrusion onlyNo heat treatment after CONFORM
CANMET-MTL CONFORM Extruded AZ31 Rods
From cast rods
Φ5 mm
From cast rods
Φ7 mm
From extruded rods
Φ5 mm
Meters long product successfully producedg p y pSurface finish depends on the feedstock, heating temperature & extrusion speedExcellent surface finish when extruded rods were used as feedstock
Produced by a Commercial CONFORM Machine Designed for Aluminum
CANMET-MTL Grain Refinement
Feedstock~150 m
Near Surface~1.5 m
Center~2 m SEM
10 µm
2 m
Cross
Significant Grain Refinement: ~150 m to ~2 m
µ Cross Sections of
the Rod
CANMET-MTL
Microstructure Characterization: High Resolution SEM
Grains in Submicrons
Near CenterNear Surface
Grains in Submicrons
CANMET-MTL
Microstructure Characterization: SEM-EDS
A
A A B
B
CANMET-MTL
Microstructure & Texture Characterization: EBSD
ED
Inverse Pole Figure Map: Extrusion DirectionInverse Pole Figure Map: Extrusion Direction