The recently commissioned 100 TW, TiSa laser system (2.5 J, 25 fs) at the University of Düsseldorf has been used to study various issues at relativistic intensities including interaction physics, electron and proton acceleration and higher surface harmonics. The plasma evolution during and after laser pulse propagation through underdense gaseous targets was investigated with an optical probe pulse. Under similar experimental conditions the electron beam was recorded with Lanex screens and an electron spectrometer. On solid thin foil targets the production of protons was studied using a magnetic spectrometer. Due to the high contrast of the laser pulse, foil targets as thin as 300 nm could be used. Higher harmonics from laser irradiated fused silica targets were observed.
In this study, compressibility, and conventional and ultra-high frequency induction sintering behaviors of 99.8% purity and 50-70 µm size range aluminum powders were investigated. In the compressibility studies, uniaxial-cold pressing method was used. Green samples were produced in the range of 50-275 MPa using different pressures. By measuring the apparent densities of the produced samples, the optimum compressibility pressure was determined as 200 MPa. Pure aluminum powder metal samples produced with this ideal pressing pressure were sintered in both classical and ultra-high frequency induction methods in the range of 500-600 o C. Sintering was performed as 40 min in the traditional method and 5 min in the ultra-high frequency induction sintering method. As a result of the tests carried out in this study, it was determined that pure aluminum samples were successfully sintered with a high frequency induction system in a shorter time than traditional sintering method.
En este estudio, se analiza la sinterabilidad de composites de matriz de aluminio reforzados con WC 1, 3, 5, 9 y 15% (en peso) y obtenidos por inducción rápida y métodos tradiconales. El procedimiento seguido fue, en primer lugar, presionar mediante un método de prensado en frío no axial con una presión de 200 MPa. Algunas de estas muestras patrones se sinterizaron mediante un método de sinterización por inducción rápida a ultra alta frecuencia, durante 300 s a temperatura de 600 °C. Otras muestras se sinterizaron a 600 °C durante 1800 s. Se midieron los valores de densidad y dureza de los composites sinterizados y se ensayaron las propiedades microestructurales, y el comportamiento de abrasión y de fricción. Se observó que si se aumentaba la relación de refuerzo de WC la resistencia a la abrasión y el coeficiente de fricción tambien aumentaban. Finalmente, el estudio mostró que la sinterización a ultra alta frecuencia es una alternativa tan válida como el método tradicional de obtención de composites de Al-WC.
El objetivo de este trabajo es investigar las propiedades mecánicas y tribológicas de refuerzos de dióxido de titanio (TiO2) en una matriz de aluminio (Al). Se utilizó aluminio de pureza 99,8% reforzado con TiO2 ensayándose cinco cantidades diferentes de dióxido de titanio. Se mezcló polvo de aluminio y TiO2 en un molino de bolas durante 30 min, utilizando un mezclador con eje descentrado. La mezcla se compactó mediante la técnica de prensado en frío a una presión de 250 MPa. Se utilizaron dos métodos diferentes para el sinterizado. El compactado en verde se sinterizó a 600 ºC durante 300 s en atmósfera ambiental con un sistema de inducción de ultra alta frecuencia (UHFIS) y con un horno convencional a 600 °C durante 1800 s. Las propiedades mecánicas y micro-estructurales de las muestras se compararon utilizando diferentes cantidades de refuerzo. La dureza máxima se observó para un refuerzo con 5% en peso de TiO2.
In this study, it was aimed to determine and compare the sinterability of aluminum-SiO2 composites by conventional and fast sintering methods and to examine their tribological properties after the sintering process. For this purpose, 1, 3, 5, 9, and 15 wt.-% SiO2 reinforced aluminum matrix composites were sintered by a conventional and induction sintering method at 600 °C after uniaxial cold pressing under 200 MPa pressure. The sintering was performed for 30 minutes for the traditional method and 5 minutes for induction sintering. After the sintering, the microstructures of the samples were examined, and their sintered densities and hardness were determined. In addition, the tribological properties of the samples were investigated by the pin-on-disc method, and the worn surfaces were examined after the tests.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.