Morphological features of interfacial intermetallics and interfacial reaction rate in Al-11Si-2.5Cu-(0.15/0.60)Fe cast alloy/die steel couples

Soldering reactions are commonly observed during high pressure die casting of aluminium alloys, and involve the formation and growth of interfacial intermetallics between the die and the cast alloy. It is generally believed that close to 1% Fe is necessary in the aluminium alloy to reduce soldering. However, the role of iron in the interfacial reaction has not been studied in detail. In this investigation, reaction couples were formed between H13 tool steel substrates and an Al-11Si-2.5Cu melt containing either 0.15 or 0.60% Fe. Examination revealed distinctly different intermetallic layer morphology. The overall growth and chemistry of the reaction layer and the reaction rate measured by the consumption of the substrate were compared for the two alloy melts. It was demonstrated that a higher iron content reduces the rate of interfacial reaction, consistent with an observed thicker compact ( solid) intermetallic layer. Hence, the difference in reaction rate can be explained by a significant reduction in the diffusion flux due to a thicker compact layer. Finally, the mechanism of the growth of a thicker compact layer in the higher iron melt is proposed, based on the phase relations and diffusion both within and near the interfacial reaction zone. (C) 2004 Kluwer Academic Publishers.

Verbal and physical aggression in couples where the female partner is drinking heavily

This study evaluated (i) frequencies of aggression in maritally distressed problem drinking (DP) women relative to controls, (ii) aggression, marital satisfaction, and partner drinking in predicting female drinking, and (iii) discrepant within-couple drinking in predicting marital distress. The sample included 27 DP women, 24 maritally distressed nonproblem drinking women (DNP women), and 24 women with neither problem (NDNP women). DP women reported frequencies of physical aggression similar to DNP women, but less male verbal aggression than DNP women. Predictors of female drinking were marital satisfaction and male drinking, but aggression did not predict female drinking. Female marital satisfaction was predicted by interspousal discrepancies in drinking after accounting for verbal aggression.