Determination of the radius of triple junctions of tilt boundaries in nickel: a molecular dynamics modeling
The distribution of free volume and energy in the region of triple junctions of high-angle tilt boundaries with the axes of misorientation <100> and <111> in nickel, formed during crystallization, was studied by the method of molecular dynamics. The crystallization was simulated from three crystal nuclei with a variable value of free volume. It is shown that the introduced free volume in the process of crystallization concentrates mainly in the region of the grain boundaries, wherein, the closer to the junction of the boundaries, the higher the proportion of free volume. The effective radius of triple junctions was determined from the distribution of energy in its region. At the <100> tilt boundaries and the junctions formed by them, the free volume during crystallization dissipates more efficiently than at the junctions formed by the <111> boundaries. For this reason, the energy radius of the triple junction of the <100> boundaries varied slightly with an increase in the introduced free volume: from 5 to 7 Å, whereas the junction radius of the <111> boundaries with the introduction of 2% of vacancies in the starting computational cell reached 14 Å.