Following the progress of sintering in steel powder compacts through original experiments

In order to evaluate the progress of sintering in powder steel compacts, two experiments were performed. First, the electrical resistivity of a die pressed compact was continuously measured during a sintering cycle up to 1130 °C inside an adapted dilatometer. The main changes occur at intermediate temperatures, since the resistivity falls by a factor of about 100 between room temperature and 800 °C and is almost constant afterwards. In the second set of experiments, partially sintered specimens are submitted to a tensile test until failure and their fracture surfaces are analysed in terms of welded area fraction of interparticle contacts..

Following the progress of sintering by measuring viscosity and electrical resistivity variations

The simplest way of characterizing the advancement of sintering of a powder is to follow the variation of its relative d. However, sintering of a dense compact, obtained for example by die pressing of iron-based powders, occurs with very low d. changes, while, of course, the microstructure and the properties of the material strongly evolve. In this study, the progress of sintering is followed by a continuous measurement of two characteristics of the material throughout sintering: the elec. resistivity and the viscosity. The original techniques developed for the measurement are presented and the interest of the data obtained for the understanding and modeling of sintering is discussed

Suivi in situ de l'avancement du frittage d'une poudre d'acier

Une manière simple de caractériser l'avancement du frittage d'une poudre est de suivre ses variations de densité relative. Cependant, pour les poudres d'acier préalablement compactées en matrice, la densité initiale est grande, par conséquent évolue peu lors du frittage. Au contraire, la microstructure et les propriétés du matériau évoluent beaucoup. Dans cette étude, l'avancement du frittage est suivi in situ au cours du frittage par deux caractéristiques physiques : la résistivité électrique et la viscosité. Les techniques innovantes développées pour ces mesures expérimentales sont présentées ainsi que l'intérêt des résultats pour la compréhension et la modélisation du frittage

Following the progress of sintering by measuring viscosity and electrical resistivity variations

The simplest way of characterizing the advancement of sintering of a powder is to follow the variation of its relative d. However, sintering of a dense compact, obtained for example by die pressing of iron-based powders, occurs with very low d. changes, while, of course, the microstructure and the properties of the material strongly evolve. In this study, the progress of sintering is followed by a continuous measurement of two characteristics of the material throughout sintering: the elec. resistivity and the viscosity. The original techniques developed for the measurement are presented and the interest of the data obtained for the understanding and modeling of sintering is discussed

Following the progress of sintering in steel powder compacts through original experiments

In order to evaluate the progress of sintering in powder steel compacts, two experiments were performed. First, the electrical resistivity of a die pressed compact was continuously measured during a sintering cycle up to 1130 °C inside an adapted dilatometer. The main changes occur at intermediate temperatures, since the resistivity falls by a factor of about 100 between room temperature and 800 °C and is almost constant afterwards. In the second set of experiments, partially sintered specimens are submitted to a tensile test until failure and their fracture surfaces are analysed in terms of welded area fraction of interparticle contacts..