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Tuesday, June 11, 2024

Why Apple Decided to Use Titanium in iPhone 15?

Apple company announced during its Wonderlust event on Tuesday that the most premium material titanium will be ever used in an iPhone. In this post, We decided to dig into the topic of why Apple decided to use such material to make their phones “more premium”.

An iPhone is a complex piece of machinery. Each phone contains a number of different metals, primarily;

  • Aluminium
  • Iron
  • Lithium
  • Gold
  • Copper

We also know from iPhone 13 release reports that in order to use more recycled material Apple also uses;

  • “Rare Earth Elements”
  • Tungsten
  • Tin
  • Plastic

However, the quantity of these materials is still in question. Back in old models, we know that there are several reports on how much materials were used in older models, such as the iPhone 6S. [1]

Infographic: The Materials That Make Up The iPhone | Statista

Particularly the term of “rare elements” are often hidden in common personal electronics. However, these elements have significant effects on iPhone models from screen resolutions to vibrations [2]

screenshot-2022-11-21-at-1-59-20-pm.png

For the iPhone 15 Pro and ‌iPhone 15 Pro‌ Max, Apple is using a new titanium frame rather than a stainless steel frame, which cuts down on weight.

What are the key points of Titanium (Ti) Element?

Chemical element, Ti, atomic number 22 and atomic weight 47.90. Its chemical behaviour shows many similarities with that or silica and zirconium. It is strong, lustrous, corrosion-resistant. Pure titanium is not soluble in water but is soluble in concentrated acids. This metal forms a passive but protective oxide coating (leading to corrosion resistance). This process is very similar to Cr2O3 which makes steel stainless.

While steel beats titanium in terms of high strength, titanium is lighter and can support more weight relative to its own. In the ads, Apple used the term of “titanium’s unique properties give it one of the highest strength-to-weight ratio of any metal” to emphasize the ductility of titanium elements.

What does this Strength-to-weight ratio mean?

Strength-to-weight ratio is a measure of the strength of an object divided by its mass or weight. It is used to determine the efficiency and performance of any given material or component. Because of this key metric, engineers are able to produce top-quality products that take up less material and are designed more efficiently.

MaterialsSpecific yield point (Yield point/km)
Titanium alloys7.7-26
Steel4.5-14
Aluminium alloys6.0-24
Strength-to-weight-factors of some roll materials [3]

Titanium also has good fatigue resistance, meaning it can withstand repeated stress cycles without failure.

Due to the fact that density plays a vital role in the weights of elements, (Density: 7.8–8 g/cm3 for steel; 4.51 g/cm3 for titanium), undoubtedly titanium will result in a lighter iPhone and the ‌iPhone 15 Pro‌ and ‌iPhone 15 Pro‌ Max are approximately nine percent lighter than the iPhone 14 Pro and ‌iPhone 14 Pro‌ Max. The ‌iPhone 15 Pro‌ weighs 187 grams, down from 206 grams for the ‌iPhone 14 Pro‌. The ‌iPhone 15 Pro‌ Max weighs 221 grams, down from 240 grams for the ‌iPhone 14 Pro‌ Max [4].

Along with lowering the weight of the iPhone, the titanium material is also less prone to fingerprints because of the new brushed finish and it is more durable.

However, it is still in question which parts will be replaced by titanium. We all know that aluminum is one of the key elements in iPhone’s frames, however, Al is a way lighter element than titanium, Therefore, it is likely that stainless steel parts will be replaced by titanium material so that a lighter iPhone is manufactured.

References

1-Statisca.com

2-https://www.macrumors.com/2023/09/12/titanium-iphone-15-pro-weight/

3-Gelfgat, Mikhail & Alhimenko, Aleksey & Kolesov, Sergey. (2019). Corrosion and the role of structural aluminum alloys in the construction of oil and gas wells. E3S Web of Conferences. 121. 04003. 10.1051/e3sconf/201912104003.

4-https://www.macrumors.com/2023/09/12/titanium-iphone-15-pro-weight/

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