Apple's first foldable smartphone, rumored to launch this fall as the iPhone Ultra, will reportedly use a liquid metal hinge. The information comes from a prolific Weibo leaker who claims development is advancing rapidly, with prototypes already sent to carriers worldwide for testing.

Liquid metal isn't actually liquid—it's an alloy with a disordered, non-crystalline atomic structure similar to glass. This gives the material exceptional elasticity, allowing it to absorb stress and return to its exact original shape. It's also stronger than titanium and stainless steel while weighing significantly less, plus it has a microscopically smooth surface that prevents wear from repeated folding.

Foldable phones face durability concerns around hinge mechanisms, which typically loosen over time. Apple's alleged solution could address this weakness, potentially offering better longevity than existing foldable designs. The hinge's ability to withstand hundreds of thousands of folds without wobbling suggests iPhone Ultra might solve a core criticism of the form factor.

The device is expected to debut in September alongside the iPhone 18 Pro lineup. While leaks should be viewed skeptically, this one aligns with Apple's history of pursuing unconventional materials for competitive advantages.