Over the years, Apple has switched from an aluminum frame to a stainless steel frame to a titanium frame for its highest-end iPhones. And now, it has been rumored that Apple will go back to using aluminum for three out of four iPhone 17 models.

In an investor note with research firm GF Securities, obtained by MacRumors this week, Apple supply chain analyst Jeff Pu said the iPhone 17, iPhone 17 Pro, and iPhone 17 Pro Max will all be equipped with aluminum frames. Interestingly, though, he expects Apple's rumored iPhone 17 Air model to have a titanium frame.

This would be a notable change for the Pro models, as all of the iPhone 15 Pro and iPhone 16 Pro models have titanium frames, resulting in the devices weighing less than iPhone 14 Pro models with heavier stainless steel frames.

Aluminum frames were already rumored for the iPhone 17 Pro models once before.

Pu said Apple plans to use aluminum for the iPhone 17 Pro models due to environmental considerations. Aluminum generally has a lower carbon footprint compared to titanium, and Apple is aiming to achieve carbon neutrality for all of its products and supply chain by 2030. Following in the footsteps of the Apple Watch, and the latest Mac mini, perhaps some iPhone 17 models will be advertised as Apple's first carbon-neutral iPhones.

It is unclear why the iPhone 17 Air would have a titanium frame, as aluminum is lighter than titanium, which would be fitting for the device's thin and light design. We may have a partial explanation, though. Last year, fellow Apple analyst Ming-Chi Kuo said the iPhone 17 Air's frame would use a mix of titanium and aluminum, with a lower amount of titanium compared to the iPhone 15 Pro models. Apple surely has its reasons here, so hopefully we will find out more details before the iPhone 17 series is unveiled in September.

Source: Macrumors