Envelhecimento na Martensita Induzida por deformação em aços tipo AISI 304

• Ano de defesa: 2006
• Autor(a) principal: Luciana Spindola Sales
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Engenharia Metalúrgica e de Minas; Engenharia metalúrgica; Martensita
• Link de acesso: http://hdl.handle.net/1843/BUOS-8DNJ3E

In this work, austenitic stainless steel AISI304 pre-strained by 25% at -5ºC was studied aming to determine the phenomenological aspects and the mechanism related to the aging process. The pre-strained conditions used in this work resulted in a volume fraction of martensite of 60%.The aging treatments were carried out in a temperature range of 80to 160ºC with time in the range of 1 to 400 minutes (60 to 2400s). It was observed that the yield stress increases with time and temperature. On the other hand, the uniform and total elongation decreases with increasing time and temperature. The equation which describes the changes in transformed fraction with time has the Harpers equation form with a time exponent of ½. This value was associated to the formation of precipitates e. The value of activation energyobtained, 65kJ/mol, suggests that the aging process is carbon controled diffusion in martensite.