Grain Boundary Area, Grain Boundary Curvature and Particle Pinning in an Al-1mass%Mn Alloy Containing Al6Mn Precipitates
The usual expression to calculate the limiting grain radius due to particle pinning is RL=ar/f, where r is the particle radius, f is the volume fraction of the particles, RL is the limiting grain radius and a is a constant equal to 1/6 according to Rios[Acta Metall. Vol. 35 (1987) p. 2805]. This form is not convenient for comparison with experimental measurements. In this work two alternative expressions are proposed: 1)SVL=3SVP where SV is the grain boundary area per unit of volume and SVP is the interface area per unit of volume and 2)H=SVP where H is the total grain boundary curvature. These expressions are compared with experimental measurements carried out in a high purity Al-1mass%Mn alloy containing Al6Mn precipitates annealed for 3600 s at temperatures ranging from 500 to 620 oC. Good agreement is obtained between theory and experiment. The relative merits and shortcomings of each expression are discussed in detail from a fundamental and experimental point of view. It is concluded that the first expression is probably the best choice for practical purposes.
B. Bacroix, J.H. Driver, R. Le Gall, Cl. Maurice, R. Penelle, H. Réglé and L. Tabourot
P. R. Rios and G.S. Fonseca, "Grain Boundary Area, Grain Boundary Curvature and Particle Pinning in an Al-1mass%Mn Alloy Containing Al6Mn Precipitates ", Materials Science Forum, Vols. 467-470, pp. 991-996, 2004