Commentaries on 'Entrainment defects' by J Campbell

In the February 2006 issue of MST (pp. 127-143) we published an invited Materials perspective by John Campbell, in which he puts the case for entrainment defects, predominantly entrained oxide films, as a powerful and economical means of explaining and interpreting the mechanical and corrosion properties of cast metals. Perspectives offer the author the opportunity for informed speculation and to advance a personal view of the development of a field. The importance and broad sweep of Professor Campbell's thesis led the Editorial Board to seek commentaries on his 'perspective' from authorities in the casting and related communities. Contributions by P. R. Beeley, J. R. Griffiths, N. R. Green and C. J. Newton appear below, followed by a response from J. Campbell. We should welcome further contributions to this discussion, which all parties have found a useful and interesting exercise.