The subgrain size and the spacing of high angle boundaries are important parameters used to describe the microstructure in metals deformed to large strains. How the flow stress depends on the boundary spacing is discussed here and it is argued that the best way this is treated is in the work hardening model developed by Nes and co-workers (Progr. Mater. Sci., 1998, 41, 129 – 193; Mater. Sci. Tech., 2001, 17, 376 – 387; Mater. Sci. Eng., 2002, A 322, 176 – 193). The theoretical arguments given are supported by experimental observations.
LANGFORDG. and COHENM.: Trans. ASM, 1969, 62, 623–638.
19.
LLOYDD. J.: Unpublished research.
20.
CASTRO-FERNANDEZF. R., SELLARSC. M. and WHITEMANJ. A.: Mater. Sci Technol, 1990, 6, 453–460.
21.
NORD-VARHAUGK., FORBORDB., BENESTADJ., PETTERSENT., RØNNINGB., BARDALA., BENUMS., MARTHINSENK. and NESE.: Proc. Int. Conf. on ‘Aluminium alloys’ (ICAA7), Charlottes-ville, VA, USA, April 2000, Mater. Sci Forum, 2000, 331–337, 1387-1392.
22.
LANGFORDG. and COHENM.: Trans. ASM, 1975, 6A, 901–910.
23.
ZEHETBAUERM. and SEUMERV.: Acta Metall. Mater., 1993, 41, 577–588.
24.
PETCHN. J.: J. Iron Steel Inst., 1953, 174, 25.
25.
HIRTHJ. P. and LOTHEJ.: ‘Theory of dislocations’; 1968, New York, McGraw-Hill.
26.
THOMPSONA. W. and BASKESM. I.: Phil. Mag., 1973, 28, 301–308.
27.
HANSENN.: Acta Metall., 1977, 25, 863–869.
28.
HORITAZ., FUJINAMIT., NEMOTOM. and LANGDONT. G.: Metall. Mater. Trans. A, 2000, 31A, 691–701.
