Apple's Custom 7xxx Series Aluminum for the 6S

A breath of fresh air (science) in the never-ending media cycle that covers new iPhone rumors.

Last week, a new iPhone bending video was released by Unbox Therapy. It compares the shell of the current iPhone 6 to that of a new shell that’s said to be from the upcoming iPhone 6S.

…Lew’s basic conclusion holds: the new shell is far stronger than the current one.

But no “basic conclusion” is complete without a visit from the X-ray fluorescence unit!

The XRF results for the current iPhone shell say it’s a 6063 aluminum. The leading “6” means the primary alloying elements are silicon and magnesium, and that’s just what the elemental breakdown shows.

The XRF results for the new shell aren’t as clearcut. While it’s obvious that zinc is the primary alloying element, which means the alloy is in the 7xxx series, the software didn’t find a good match in its database.

The assumption being that the new shell is made from the same (or similar) custom aluminum alloy that was so widely touted for the launch of the Apple Watch Sport.

For example, a fully annealed 6063 (6063-O) has a yield strength of about 7,000 psi, while a solution heat treated and artificially aged 6063 (6063-T6) has a yield strength of about 31,000 psi.

By comparison, if we look at the typical properties of a 7075 alloy (commonly used in aircraft parts), the fully annealed (7075-O) yield strength is 15,000 psi and the solution heat treated and aged (7075-T6) yield strength is 73,000 psi.

So it sounds like we’re going to have significantly less bendgate this coming fall.


Tue, Aug 25, 2015