Determination of Relation between Elastic Constant and Si ntered Temperature in WC-Ni Composites
In this study we have investigated relation between elasti c constant and sintered temperature in tungsten carbide- nickel composite samples. Determination of elastic properties of materials is based on the transverse and longitudinal wave’s velocities via ultrasonic methods. In this study ultrasonic velocity measurements were measured in the WC-Ni composites. These samples are formed by powder metallurgy and electroless plating. Samples were sintered at temperat ures of 1000 °C, 1100 °C, 1200 °C and 1300 °C with Ar gas atmosphere in tube furnace. In the measuring ultrasonic longitudinal velocity 2 and 5 MHz transducers, ultrasonic transverse velocity 1 and 5MHz transducers have been used. Young Modulus (E) has been calculated by using longitudinal and transverse velocity. A fter we calculated elastic constant, we have investigated relation between sinter ed temperature and elastic constant of samples. A linear relation between sinter ed temperature and elastic constant in samples is observed.
Determination of the elastic constants of metal-matrix composites by a laser ultrasound technique
Abstract The longitudinal and transverse ultrasonic wave velocities of a series of as-cast short-Al 2 O 3 -fiber-reinforced SAE321 matrix composites (Al 2 O 3f /SAE321) and SiC-particle-reinforced ZA-27 matrix composites (SiCp/ZA-27) in the as-cast conditions were measured by a laser ultrasound technique. The experimental results showed that the wave velocities in two composites varied with the volume fraction, f , and the size of the ceramic reinforcements within the metal matrix. The interfacial structures and metallurgical defects of the composite played an important role in the variation of ultrasonic wave velocities. The effective elastic constants of the composites, including Young's modulus, E , the shear modulus, G, Poisson's ratio, ν , and the Lame coefficient, λ , were calculated by using the values of the velocities and the mass densities of composites according to the elastic theory of solids. As expected, the Young's modulus and shear modulus of as-cast Al 2 O 3f /SAE321 composites monotonically increased with increasing volume fraction of the reinforcement. The elastic constants of SiCp/ZA-27 composite with a volume fraction of 0.05 in the as-cast conditions were essentially larger than that of the monolithic alloy and tended to increase with the particle size. However, property deterioration was observed when the particle volume fraction was above this level. It is believed that a thin layer of oxidation inclusions and microvoids at the interface observed by transmission electron microscopy (TEM) as well as metallurgical defects (SiC particle segregation, shrinkage pores and gas-blows) by scanning electron microscopy (SEM) may be responsible for the property degradation.
Nietzsche: Philosopher, Psychologist, Antichrist
This classic is the benchmark against which all modern books about Nietzsche are measured. When Walter Kaufmann wrote it in the immediate aftermath of World War II, most scholars outside Germany viewed Nietzsche as part madman, part proto-Nazi, and almost wholly unphilosophical. Kaufmann rehabilitated Nietzsche nearly single-handedly, presenting his works as one of the great achievements of Western philosophy. Responding to the powerful myths and countermyths that had sprung up around Nietzsche, Kaufmann offered a patient, evenhanded account of his life and works, and of the uses and abuses to which subsequent generations had put his ideas.Without ignoring or downplaying the ugliness of many of Nietzsche's proclamations, he set them in the context of his work as a whole and of the counterexamples yielded by a responsible reading of his books. More positively, he presented Nietzsche's ideas about power as one of the great accomplishments of modern philosophy, arguing that his conception of the "will to power" was not a crude apology for ruthless self-assertion but must be linked to Nietzsche's equally profound ideas about sublimation.He also presented Nietzsche as a pioneer of modern psychology and argued that a key to understanding his overall philosophy is to see it as a reaction against Christianity. Many scholars in the past half century have taken issue with some of Kaufmann's interpretations, but the book ranks as one of the most influential accounts ever written of any major Western thinker.