When you think about the word LiquidMetal, what immediately comes to mind is the reforming face of Robert Patrick in The Terminator 2 movie. And truth be told, you wouldn’t be very far off. In essence what LiquidMetal along with Vitreloy are commercial names of a series of amorphous metal alloys developed by a research team from the California Institute of Technology. All subsequent discoveries by the team have been marketed by a company called Liquidmetal Technologies. As of late, there have been rumors floating about the internet of devices coming out in cases made of liquidmetal like the upcoming next-gen iPhone and even the next range of MacBook Pros. And after posting about the rumors, we decided that it is essential to understand more about what this amorphous metal alloy really is so we delved deeper.
Liquidmetal alloys bring with it desirable material features such as a high tensile strength, excellent corrosion resistance, very high coefficient of restitution (reformation), excellent anti-wearing characteristics, heat forming process similar to thermoplastics and despite the name, it is not liquid at room temperature. The material was introduced for commercial application in 2003 and has found its way to golf watches, cell phone casings, watches and even the SIM-ejector tool for the iPhone 3GS a while back. It was first discovered in a series of experimental alloys that could achieve an amorphous structure that had relatively slow cooling rates which allowed it to be molded into complex shapes as opposed to crystalline metals like steel. The alloys retain their amorphous structure after a repeated re-heating which leads to a wide variety of traditional machining processes.There are a few reasons why liquidmetal is the preferable material to work with. One key difference is that crystalline metals have no obvious melting point and after a short time, the viscosity (water has low viscosity while oil has high viscosity) drops drastically due to its rapid cooling rate. On the other hand, liquidmetal’s viscosity drops gradually with increased temperature thus allowing it to shaped or molded and generally easier to handle. When temperature lowers, the increased viscosity prevents the atoms from moving enough and forms strong ordered lattice bonds for a solid and strong structure. As opposed to crystalline metals which have to be forged or wrought, liquidmetal can be cast or molded in liquid form into complex shapes and therefore can be used as replacement for complex parts usually found in plastic.
With regards to the strength of the metal, liquidmetals made from a mixture of zirconium and titanium alloy yield strength of 1723MPa (Mega Pascal) of energy which is said to be twice the strength of crystalline metals that yield a strength of 830MPa. That said however during its infancy, there were casting methods for liquidmetal that introduced microscopic flaws and rendered the lattice structure unstable. This meant that when the metal was struck, it simply shattered. After many years of research though, newer casting methods along with various combinations of alloy mixes have led to a tremendous improvement in this aspect.
What can it be used for?
Liquidmetals have a place in the consumer technology world but there is one thing that makes this particular resource hard to come by and that is the exorbitant price it carries. In certain devices like the expensive Vertu phone casings, there is liquidmetal present but in that case the price would not be an issue due to the stature of the phone. Liquidmetal is touted as being the ideal replacement for Titanium in applications ranging from medical instruments and cars to military and aerospace industry related endeavors.
It not only has an extremely high yield of strength but also an excellent strength to weight ratio but as mentioned above, the only factor standing in the way of a wider scope of use is its heavy price. In an attempt to resolve this situation, there are studies currently ongoing about a possible alloy mixture involving iron that would bring about a percentage of characteristics contained by liquid metal but will apparently make it 2-3 times stronger than the best steel around. In addition to that, it will be even lighter and would make materials like aluminum and titanium; a lightweight material of the past. In addition to that, if claims from the research group are true, it will be cheaper as well so that will help scale down the hurdle to subsequently allow this material to feature more broadly in our daily endeavors.