Simulating Molecular Amorphous Metals to Determine Bond Strength and Yield Strength

Team: 18

School: La Cueva High

Area of Science: Chemistry

Interim: Team 18 Interim Report
Mentor: Timothy Lester Thomas

Most metals exhibit a crystalline structure that makes it nearly impossible to accurately measure yield strength at the atomic level. This is because the grain boundaries of the metal catch shifts and cleaves and cannot be predicted. Thus, modern yield strengths for metals at the atomic level are based on scaled data from physical durability tests. This isn’t the case for amorphous metals (aka Bulk metallic glass (BGM) materials), however, which have the unique attribute of exhibiting “liquid” structures. These “liquid” structures are organized through a variety of idiosyncratically shaped metal atoms in order to produce a fluid-like structure with strong bonds. Most notably, amorphous metals display higher tensile and yield strength than even the strongest pure metals like titanium, as well as low Young’s moduli and greater Vickers hardness (Lu). Furthermore, the lack of a rigid structure allows amorphous metals to absorb and reflect energy with minimum energy loss. This kind of alloy is perfect in the commercial creation of printed electric circuits and semiconductor devices as well as solder bumps for communication between integrated circuit devices.

Problem solution:

We simulated the structure of Vitreloy, a commercially available amorphous metal, and the intellectual property of Eutectix. We measured Vitreloy’s assortments of Zr, Be, Ti, Cu, and Ni in order to measure its strength on the atomic bonding level. With this knowledge, we can both measure the strength of an amorphous metal at the bonding level and use Vitreloy to a greater effect.

Progress to date:
Currently, we have a rudimentary model of Vitreloy through simulated bonding of Zr, Be, Ti, Cu, and Ni atoms created using the Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). Our current predictions have yielded roughly 1.83 GPa in tensile yield strength, magnitudes greater than the yield strength of competing aluminum and titanium alloys. Our measurements, although not the most accurate as of now, seem to coincide with physical durability tests done by Materion within 1 standard deviation.

We are working on extending the model to match the more randomized fluid structure of many molecules of Vitreloy in order to simulate actual uses. We are also experimenting with ductile metal enforced BMG composites (including Vitreloy) to measure the plastic deformation of amorphous metals.

Team Members:

  Mario Sumali
  Rahul Chalamala
  Charles Zhou
  Berkan Dokmeci

Sponsoring Teacher: Yolanda Lozano

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