Abnormal correlation between phase transformation and cooling rate for pure metals.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Phase transformation dynamics during rapid cooling are crucial for metallic glass production.
• Understanding crystallization scatter is key to controlling material properties.

Purpose of the Study:

• To investigate phase transformation phenomena during rapid cooling in pure metals.
• To elucidate the physical origins of scatter in crystallization times.
• To establish correlations between cooling rates and phase selection (crystal vs. glass).

Main Methods:

• Molecular dynamic simulations were employed.
• 14 pure metals were analyzed, with a focus on pure copper.
• Analysis of bond-orientation order at various cooling rates.

Main Results:

• A critical cooling rate region (6.3 × 10^11–16.6 × 10^11 K/s) was identified where crystalline fractions fluctuate significantly.
• Glass transformation is influenced by atomic structure fluctuations governed by thermodynamic factors.
• Two distinct mechanisms for glass formation were proposed based on cooling rates.

Conclusions:

• Kinetic retardation of atomic rearrangement at high cooling rates hinders crystallization.
• Competition between icosahedral and crystal orders near critical rates influences glass formation.
• The study provides deep insights into the physics of rapid solidification in metals.