• Para o aço 15Kh2MFA puro, o tratamento térmico de normalização foi suficiente para a obtenção da estrutura bainítica, apesar de que, quando a temperatura foi aumentada, o valor de microdureza diminuiu. Isto pode estar associado à descarbonetação do aço;
• Após a normalização, a adição do carbeto de nióbio no aço 15Kh2MFA não influenciou de forma significativa os valores de microdureza e microestrutura das amostras que foram apenas sinterizadas.
SUGESTÕESPARATRABALHOSFUTUROS
A fim de preencher as lacunas que ainda existem a cerca deste tema, a seguir serão relacionadas algumas sugestões para trabalhos futuros:
• Utilizar atmosfera carbnonizante como, por exemplo, o gás metano para evitar a descarbonetação do sistema;
• Estudar diferentes quantidades de NbC neste aço para avaliar o efeito nas propriedades mecânicas e na microestrutura;
• Utilizar outros carbetos como o carbeto de titânio, carbeto de molibdênio e carbeto de tungstênio para observar se estes terão o mesmo comportamento do carbeto de nióbio;
• Utilizar um forno a plasma para avaliar a influência da taxa de aquecimento e o comportamento da sinterização;
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APÊNDICE–PARÂMETROSDE
REDE
Sistema cristalino cúbico com grupo espacial Im-3m.
Figura A - 1. Parâmetros de rede para o Ferro-Manganês (Fe19Mn). Sistema cristalino cúbico com grupo espacial Im-3m.
Sistema cristalino cúbico com grupo espacial Im-3m.
Figura A - 3. Parâmetro de rede para o Ferro-Molibdênio (Fe9,7Mo0,3).
Sistema cristalino cúbico com grupo espacial Im-3m.
Sistema cristalino cúbico com grupo espacial Im-3m.
Figura A - 5. Parâmetros de rede para o Ferro (Fe).
Sistema cristalino tetragonal com grupo espacial I4/mmm.
Sistema cristalino cúbico com grupo espacial Im-3m.
Figura A - 7. Parâmetro de rede para o Cromo-Ferro-Vanádio (VCrFe8).
Sistema cristalino cúbico com grupo espacial Im-3m.
Sistema cristalino ortorrômbico com grupo espacial Pnma.
Figura A - 9. Parâmetros de rede para o Carbeto de Ferro (Fe3C).
Sistema cristalino hexagonal com grupo espacial P63mc.
Sistema cristalino cúbico com grupo espacial Fm-3m.
Figura A - 11. Parâmetro de rede para o Carbeto de Tântalo (TaC).
Sistema cristalino cúbico com grupo espacial Fm-3m.
Sistema cristalino cúbico com grupo espacial Fm-3m.
Figura A - 13. Parâmetros de rede para o Carbeto de Nióbio (NbC0,87).
Sistema cristalino cúbico com grupo espacial Pm-3m.
Sistema cristalino cúbico com grupo espacial Fm-3m.
Figura A - 15. Parâmetros de rede para o Carbeto de Nióbio-Cromo (Cr0,1Nb0,9C).
Sistema cristalino cúbico com grupo espacial Im-3m.