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INTRODUCTION

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ALTHOUGH it has long been recognized that the grains of a polycrystalline metal are far from being uniform in either shape or size, this factor and its consequences have received relatively little attention from physical metallurgists. Measurements of the volume distribution of grains have been made in /3-brass by Hull, ~ in aluminum by Williams and Smith, 2 in steel by Otala, 3 and in titanium by Okazaki and Conrad, 4 the latter having pointed out that the distribution is characteristically log-normal. The present research has verified the log-normal distribution (Figure 1) in recrystallized aluminum and has shown, further, that the standard deviation of the distribution (In o'v) is subject to control by the degree of prior cold work (Figure 2). The structural differences thus revealed are very substantial and should be ex99.9~

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