Titanium Grade 5, also known as Ti-6Al-4V, is a material used in the manufacturing of the iPhone 15 casing and Mars surface exploration spacecraft.

Titanium Grade 5 is a durable, strong, yet lightweight material chosen by Apple to serve as the protective armor for their new smartphone lineup.

A durable, robust, yet lightweight material chosen by Apple to serve as the protective armor for their new smartphone lineup.

At the Wonderlust event held in the early morning of September 13th (Vietnam time), Apple unveiled a series of new devices, eagerly anticipated by tech enthusiasts worldwide. As usual, the iPhone smartphones took center stage with new materials, new buttons, a new chip, and a series of notable upgrades.

However, for many users, what they are interested in is the appearance of the latest iPhone 15 models. Understanding the aesthetic passion of iFans, Apple announced titanium as the unprecedented material for the phone casing, along with a range of colors affirming the brand’s identity, including Black Titanium, White Titanium, Blue Titanium, and Natural Titanium.

And there’s one more thing…

Onstage, Isabel Yang, Apple’s material science engineer, affirmed that the alloy used in the latest iPhone model is called Titanium Grade 5, which is also used in the construction of Mars surface exploration spacecraft. Believed to have “higher strength than pure titanium,” Apple asserts that the iPhone 15 will be more durable, flexible, and lighter than previous iPhone models.

So, where does this Titanium Grade 5 material come from and why is it so versatile?

Known as Ti-6Al-4V or also TC4, Ti64, or ASTM Grade 5, this alpha-beta titanium alloy has high strength and corrosion resistance. It finds applications in the aerospace industry and in biomedical devices (such as implants or prosthetics). Ti-6Al-4V is notably used in the manufacturing of Boeing 787 aircraft.

The pioneer behind Ti-6Al-4V is Stanley Abkowitz (1927-2017), an industry leader in titanium who invented this super-strong material while serving in the U.S. military. In tests, the maximum stress* of Ti-6Al-4V reached 950 megapascals (MPa). For comparison, the stress for concrete ranges from 2-5 MPa, pure titanium is 344 MPa, spider silk is 1,400 MPa, Kevlar (used in bulletproof vests) is 3,620 MPa, and the super material graphene is 130,500 MPa. Roughly estimated, the stress of Titanium Grade 5 is up to 190 times that of concrete.

Stress is a physical quantity that reflects internal forces generated within a deformed object due to external forces like temperature, weight, or tension.

The tests also showed that when placed under room temperature conditions, Ti-6Al-4V has very low thermal conductivity, making it difficult to process. This indicates that engineers had to work very hard to apply Ti-6Al-4V in production. It’s unclear how the low thermal conductivity of Titanium Grade 5 affects the heat dissipation capabilities of the iPhone 15 series.

Thanks to its durability and flexibility, Ti-6Al-4V continues to be trusted in the manufacturing of racing cars, airplanes, and Mars exploration spacecraft. The newly released iPhone 15 series is another testament to the flexibility of Titanium Grade 5. Perhaps, after Apple’s new product launch, more people will become aware of the existence of this lightweight yet durable and robust titanium alloy.