Steel, owing to its strength, affordability and ease-of-production, has been the most dominant Iron alloy and has been mechanizing our industries for several decades now, replacing other Iron compositions. However, even Steel, the backbone of our Civilization, is evolving along with newer technologies and necessities.
Titanium (Credit: Alchemist-hp)
Polymers have been on the forefront of materials technology, along with certain other, more expensive, metals revolutionizing industries. Steel, however, is not far behind.
Scientists are discovering newer concepts and techniques to make the Iron alloy better, lighter and stronger.
And so, scientists have developed a new way of producing Steel by alloying it with Titanium, a metal extensively consumed by mission critical industries such as Aerospace. Titanium is the ninth most abundant metal in Earth’s crust.
The Concept
Material scientists at Pohang University of Science and Technology announced a major breakthrough of forming a new type of flexible, ultra-strong, lightweight titanium steel.
This new alloy has a strength-to-weight ratio comparable to the hardest tempered titanium alloys. But since Titanium is in a smaller proportion, it, reportedly, comes at one-tenth the cost of making Ti alloys.
The researchers claim that the new alloy can be used extensively in Automotive, Aerospace, Construction and allied fields.
What Makes It Steel-Titanium Special
In the 1970’s, Soviet-era researchers discovered that adding aluminum to Steel makes the latter an incredibly strong and lightweight metal. But there was a problem – brittle fracture. Although the fracture occurred at very high limits of force, it would break rather than bend (bent steel is less problematic) beyond that limit.
This brittleness is because when alloying aluminum and Steel, many atoms in the two elements would inevitably fuse to form tough, crystalline structures that would break beyond a limit.
The idea here is to add elements that would prevent the crystalline structure from splintering.
The effort taken by the scientists involves heat-treating and then thin rolling the aluminium steel to control when and where the crystals were forming. The team also discovered that adding a small percentage of nickel offered even more control over the properties of the crystalline structure.
The South Korean team claims that adding Titanium atoms to the aluminium Steel alloy prevented the formation of crystalline structures altogether as higher temperatures were involved. Upon reaching a certain limit, the new material would now bend rather than break, thus avoiding brittleness entirely.
The new alloy is also 13% less dense than steel, making it lighter and thus higher in strength-to-weight ratio.
Challenges
But before it can be mass-produced, researchers must confront a major production issue – steelmakers currently use a silicate layer to cover and protect mass-produced Steel from oxidation and contamination. But the same silicate cannot be used to mass-producing the new steel-titanium alloy as silicate has a tendency to react with aluminum at lower temperatures. A new protection method is in way.
Conclusion
The results achieved by the researchers at Pohang University have opened the floodgates to other, newer super-steel alloys.
