1. Departamento de Engenharia de Materiais, Univ. of Sao Paulo, Av. Trabalhador São Carlense, 400 CEP:13566-590, Sao Carlos, SP, BR (Corresponding author), e-mail: rosa_simencio@yahoo.com.br
2. Departamento de Engenharia de Materiais, Univ. of Sao Paulo, Av. Trabalhador São Carlense, 400 CEP:13566-590, Sao Carlos, SP, BR
3. G. E. Totten & Associates, P.O. Box 55518, Seattle, WA 98155 US
4. Department of Mechanical and Materials Engineering, Portland State University, 1930 SW 4th Avenue, Suite 400, Portland, OR 97007 US