INTERNAL FRICTION AND DILATOMETRIC QUANTITATIVE ANALYSIS OF THE ISOTHERMAL MARTENSITIC TRANSFORMATION IN Fe-Ni-C ALLOYS

Nous montrons que le frottement intérieur est proportionnel au coefficient de dilatation lors de la transformation martensitique isotherme d'alliages Fe-Ni-C. Aucune contribution liée à la mobilité des dislocations n'étant observée, nous suggérons que le frottement intérieur est dû uniquement à la mobilité de l'interface γ-α'.Internal friction is shown to be proportional to expansivity during the isothermal martensitic transformation of Fe-Ni-C alloys. Since no contribution due to dislocation mobility was observed in our internal friction results, we suggest that internal friction is due only to the mobility of the γ-α' interface

CORRÉLATION ENTRE LE FROTTEMENT INTÉRIEUR ET LE COEFFICIENT DE DILATATION LORS DES TRANSFORMATIONS MARTENSITIQUES ISOTHERMES

Nous montrons que le frottement intérieur est proportionnel au coefficient de dilatation lors de la transformation martensitique isotherme d'alliages Fe-Ni-C. Ce résultat montre que le formalisme proposé par Delorme dans le cas des transformations martensitiques athermiques peut être étendu aux transformations martensitiques de type isotherme.Internal friction is shown to be proportional to expansivity during the isothermal martensitic transformation of Fe-Ni-C alloys. This indicates that the formalism proposed by Delorme for athermal martensitic transformations can be extended to isothermal martensitic transformations

LOW TEMPERATURE INTERNAL FRICTION AND DILATOMETRIC RESULTS OBTAINED DURING THE MARTENSITIC TRANSFORMATION OF Fe-Ni-C ALLOYS

The influence of interstitial alloying elements such as carbon and hydrogen on the austenite to martensite transformation during cooling was studied in Fe-Ni-C alloys having subzero Mb temperatures. These alloying elements seem to have similar chemical and mechanical effects on the γ → α' transformation

Qualidade de silagens de sorgo com aditivos Quality of sorghum silages with additives

Um delineamento inteiramente ao acaso, com três repetições, foi utilizado para avaliar os efeitos da adição de 0,5% de uréia, de 0,5% de carbonato de cálcio (CaCO3), de 0,5% de uréia mais 0,5% de CaCO3 e de inoculante bacteriano sobre o pH, teores de matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), hemicelulose, celulose, lignina, carboidratos solúveis, ácido lático e ácido acético sobre a digestibilidade in vitro da matéria seca (DIVMS) de silagens de quatro híbridos de sorgo (BR700, BR701, BR601 e AG2002). Os híbridos ensilados sem a adição de aditivos constituíram o grupo-controle. De cada genótipo foram coletadas três amostras do material original (MOR). Foram utilizados 60 silos de PVC com 10cm de diâmetro interno e 50cm de comprimento, sendo três por tratamento. A abertura dos silos ocorreu depois de 56 dias de fermentação. As silagens contendo CaCO3 e inoculante bacteriano apresentaram, em geral, características muito semelhantes às do controle. A adição de uréia e de uréia mais CaCO3 às silagens resultou em aumento (PA completely randomized design with three replicates was used to evaluate the addition effects of 0.5% urea, 0.5% calcium carbonate, 0.5% urea plus 0.5% calcium carbonate, and bacteria culture (according to producer recommendations) on quality of four hybrids sorghum silages (BR700, BR701, BR601 e AG2002). All hybrids ensiled with no additives were used as the control group. The pH and the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), hemicellulose, cellulose, lignin, soluble carbohydrates, lactic and acetic acids, and the in vitro dry matter digestibility (IVDMD) values were determined. Three samples of each original material (MOR) were collected and analyzed. Sixty "PVC" experimental silos with 10cm of internal diameter and 50cm of length, three by treatment, were used. The silos were open after 56 days of fermentation. The results of silages containing calcium carbonate or bacteria culture were, in general, similar to the control group (without additives). The addition of urea and urea plus calcium carbonate to silages improved their CP contents (P<0.05). The addition of urea plus calcium carbonate did not improve the CP contents of silages in relation to the addition of only urea. The addition of urea can be recommended for silages of BR700, BR601 and AG2002 hybrids