I have tested the cold worked AA 6063 aluminium alloy for the tensile strength. The composition of the alloy is matching with standards. But the strength was very poor in this case. Which has no matches at any conditions like cold worked, heat treated or aged. What are the possible reasons behind this.?
Some more details are needed in your question. Did you buy AA6063 in cold worked condition? Who is your supplier? or Did you cold work after buying AA6063? In the latter case what was the initial condition (rolled or extruded) of AA6063?
How much strength did you measure?
Dear professor.,
Supplier is NALCO. While buying, it was in sheet form and cold worked after buying it.
How much strength did you get? At least around 180-220 MPa after cold working.
AA6XXX series derives its peak strength mostly from precipitation heat treatment (T6 or T4). It may reach upto 330-360 MPa upon T6 heat treatment. Sometimes, this series may not show higher strength upon cold working.
AA5XXX series aluminum alloys are suitable for strain hardening.
Please refer the following article for further info.
M. MANSOURINEJAD, B. MIRZAKHANI, Influence of sequence of cold working and aging treatment on mechanical behaviour of 6061 aluminum alloy, Transactions of Nonferrous Metals Society of China 22(2012) 2072−2079.
I have got around 160 MPa only (for three specimens)...
It should be within the limit..? What are the general factors behind this reduced strength..?
Thank You Professor.
Dear Thangapandian A N ,
Cold working might have induced natural overaging. Besides, in case the reported values are UTS, then these values are more or less in line with what can be expected for this alloy.
Hello,
The mechanical strength of the group AA60hh depends on the added alloying elements (chemical elements Fe, Cu, Mn, Mg, Zn, Ti, Cr, and Si), by way of the I receive (method of casting - gravity, centrifugal or vacuum centrifuge, etc.). , the method of processing (extrusion, rolling, extrusion, etc.) and the type of the intermediate thermal treatment. All these peculiarities will provide different mechanical properties on the group AA60hh. The amount of the alloying elements when they are in the lower limit leads to reduced mechanical properties and better flow properties. With increase in the amount of alloying elements started increasing mechanical properties but greatly reduces the ductility. Perhaps this is the reason for these low performance of mechanical strength.
Once plastic deformation in the cold group AA60hh is hardening and exhibit high mechanical properties in the original state but with this reducing the possibility of plasticity. In order to improve the flexibility, a number of intermediate annealing at a rolling sheet mateiali to achieve the desired thickness of the sheet material.
My question is related untoward if you do chemical analysis of raw material supply and microstructures have a plan in the afternoon section?
Hi Dear,
Could you please check the strain rate and testing temperature? Because strain rate and working temperatures are influencing the Mechanical behavior.
for example, In Mg alloys decrease the strain rate from 0.001 mm/s to 0.00001 mm/s, it increases the strain rate sensitivity and decreases the hardening.
In addition, grain size also an important role on mechanical behavior. because the above said not suitable for course gain size.
Also, please check the cold working parameters. That parameter also can influence the mechanical behaviour.
All the very best.
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