11.D16 We are asked to specify a practical heat treatment for a 2014 aluminum alloy that will
produce a minimum yield strength of 345 MPa (50,000 psi), and a minimum ductility of
12%EL. From Figure 11.25(a), the following heat treating temperatures and time ranges are
possible to the give the required yield strength.
Temperature (°C) Time Range (h)
260 not possible
204 0.3-15
149 10-700
121 300-?
With regard to temperatures and times to give the desired ductility [Figure 11.25(b)]:
Temperature (°C) Time Range (h)
260 <0.02, >10
204 <0.4, >350
149 <20
121 <1000
From these tabulations, the following may be concluded:
It is not possible to heat treat this alloy at 260°C so as to produce the desired set of
properties--there is no overlap of the two sets of time ranges.
At 204°C, the heat treating time would need to be about 0.4 h, which is practical.
At 149°C, the time range is between 10 and 20 h, which is a little on the long side.
Finally, at 121°C, the time range is unpractically long (300 to 1000 h).
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