artificial ageing
artificial ageing
(OP)
Hi, I am investigating the influence of the accelerated or multi-step ageing of aluminium alloys (from T1 to T2 where T1>T2) to the time and strenght, does anyone have any article about this subject or any reccomendation
Best Regards
Alpay Karampas
alpay_karampas@hotmail.com
Best Regards
Alpay Karampas
alpay_karampas@hotmail.com





RE: artificial ageing
To answer your second question, there is information on the internet under key words like “age hardening of aluminum alloys” that might provide general information. If you have access to any college books on Materials Science/Engineering, this could be of help in explaining the precipitation hardening mechanism and dependency on time and temperature. I could direct you to metallurgical engineering text books, but I doubt that you would have these references handy. I also doubt that you will find any specific data that would answer your question.
Your last option is to run your own basic laboratory experiments regarding time and temperature for aging of a heat treatable aluminum alloy like 6061. You can vary the time and temperature and plot the hardness of the aluminum alloy. This would allow you to establish your own correlations.
RE: artificial ageing
Best Regards
Alpay Karampas
RE: artificial ageing
Also AFAICR (As Far As I Can Remember) it is more important to have more homogeneous neucleation than it is to do it quickly. If the temp is too high you can get a few large precipitates instead of the preferred numerous small ones.
Also at some state of growth the precipitates can be come discontinuous with the matrix casing a consequent reduction in strength.
Nick
I love materials science!
RE: artificial ageing
RE: artificial ageing
Best Regards
RE: artificial ageing
Why are you interested in a two step aging process? The shortest aging time would be accomplished by a single aging step at an optimized temperature. For example, select 180 deg C and hold for 5 hours.
RE: artificial ageing
RE: artificial ageing
How was your material solution treated?
RE: artificial ageing
solution temp. Ageing Temp1(deg) Ageing Temp2(deg)
500 165(2hours) 215(up to 3)
500 165(3hours) 215(up to 3)
500 165(4hours) 215(up to 3)
520 165(2hours) 215(up to 3)
520 165(3hours) 215(up to 3)
520 165(4hours) 215(up to 3)
540 165(2hours) 215(up to 4)
540 165(3hours) 215(up to 4)
540 165(4hours) 215(up to 4)
I wanted to send you the graph but I dont have it as a soft copy.The conventionally aged alloy reaches its peak some three hours later than this method.
RE: artificial ageing
You should perform a literature search on this subject. Try Scirus at:
http://www.scirus.com
metengr,
The reason for two-step ageing is to reduce costs. Theoretically, the best heat treatment will use a low temperature for the first step to form small, widely-dispersed particles. Then, a higher temperature is used to artificially age the structure to peak strength in less time (with less fuel and cost) than it would take at the low temperature. Many aluminium alloys use heat treatments that are on the order of 24 hours, so shortening them to just a few hours can be a huge cost savings.
Regards,
Cory
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: artificial ageing
RE: artificial ageing
Here is an article I found that might be of interest to you;
http:/