Fe, C 0.75 (wt%) steel, quenched and tempered
This is an example of a quenched and tempered steel. The steel is initially quenched from the austenite phase field to form hard and brittle martensite. Subsequently the steel is reheated to allow diffusion of the interstitially trapped carbon and hence reduction of the lattice strain. This results in a softer and tougher steel.
Fe, C 0.75 (wt%) steel, quenched and tempered
This is an example of a quenched and tempered steel. The steel is initially quenched from the austenite phase field to form hard and brittle martensite. Subsequently the steel is reheated to allow diffusion of the interstitially trapped carbon and hence reduction of the lattice strain. This results in a softer and tougher steel.
Efficient Computer-User Interface in Electronic Mail Systems
This research explores the question of improving user- computer interface. The approach is one of observing and codifying various parameters that influence the efficiency of interface in the context of electronic mail tasks. In the paper the authors observe 'expert' and 'regular' users of a mail system and analyze the sources of efficiency. It is clear that experts use a different, more specialized, set of commands in performing standard mail tasks. While experts perform these tasks with fewer e
Fe, C 2, Mn 0.7 (wt%) steel, quenched, producing martensite
This steel was quenched from the austenite phase field too rapidly for carbon to diffuse out and form cementite. This resulted in the formation of the brittle martensite phase.
Fracture surface in a liquid crystalline polymer
Above their melting point, liquid crystalline polymers exhibit a mesophase within which, although able to flow and are not arranged in a crystal, they exhibit long range orientational order. This molecular alignment can be exploited to make high strength and stiffness fibres such as Kevlar, or even mouldable thermotropics such as Vectra. Molecular alignment can also be controlled by an external applied field; a property exploited in liquid crystal displays. This specimen has not had a magnetic f
3-Axis CNC Milling in Architectural Design
Physical scale models still have a role in architectural design. 3-axis CNC milling provides one way of making scale models both for study purposes and for presentation in durable materials such as wood. We present some types of scale models, the methods for creating them and the place in the design process that scale models occupy. We provide an overview of CNC milling procedures and issues and we describe the process of how one can creatively develop appropriate methods for milling different t
Hypoeutectoid steel, normalised at 1100°C
A hypoeutectoid alloy (carbon composition less than eutectoid). The first phase formed upon cooling from the austenite phase field is proeutectoid ferrite. Due to the lower solubility of carbon in ferrite, carbon is partitioned into the remaining austenite. At the eutectoid point the remaining carbon enriched austenite transforms to pearlite (a mixture of ferrite and cementite) which is the darker region of the micrograph. The proportion of pearlite is dependent upon the overall composition. The
Fe, C 1.1 (wt%) steel, normalised hypereutectoid
An example of a hypereutectoid steel (one that has a carbon composition above that of the eutectic). Upon cooling from the austenite field, the first phase to form is cementite on the austenite grain boundaries. This partitions iron and at the eutectic composition pearlite is formed from the remaining enriched austenite.
Austenitic stainless steel
This is a transmission electron micrograph taken at 200 kV, from a thin foil sample of "302AA" austenitic stainless steel. The sample was cold-deformed by rolling and then annealed at 704 °C for one hour. The image shows a beautiful picture of annealing twins. Notice how the ends of annealing twins are flat, the shape being determined by a minimisation of interfacial energy. Mechanical twins, by contrast, are lenticular (lens like) with sharply pointed ends to minimise the strain energy due to
Recursos de anima??o digital para aprendizagem de leitura de plantas [Digital Animation Resources fo
This paper discusses the evolution of the technical resources employed in a website destined for the professional formation of constructors workers throught the interpretation of plans. Developed as a doctoral thesis in the Ph.D. program of Information Technology in Education, the reconstruction of the website is assimilating new resourses of digital animation, allowing a richer and more significative interaction, acording to the principles of Piaget's theory on constructivism that oriented the
Fe, C 1.3 (wt%) steel, annealed at 1000°C
An example of a hypereutectoid steel (one that has a carbon composition above that of the eutectic). Upon cooling from the austenite field, the first phase to form is cementite on the austenite grain boundaries. This partitions iron and at the eutectic composition pearlite is formed from the remaining enriched austenite.
Fe, C 1.3 (wt%) steel, annealed at 1000°C
An example of a hypereutectoid steel (one that has a carbon composition above that of the eutectic). Upon cooling from the austenite field, the first phase to form is cementite on the austenite grain boundaries. This partitions iron and at the eutectic composition pearlite is formed from the remaining enriched austenite.
Fe, C 1.3 (wt%) steel, normalised at 1050°C
An example of a hypereutectoid steel (one that has a carbon composition above that of the eutectic). Upon cooling from the austenite field, the first phase to form is cementite on the austenite grain boundaries. This partitions iron and at the eutectic composition pearlite is formed from the remaining enriched austenite.
Fe, C 1.3 (wt%) steel, annealed at 1100°C
An example of a hypereutectoid steel (one that has a carbon composition above that of the eutectic). Upon cooling from the austenite field, the first phase to form is cementite on the austenite grain boundaries. This partitions iron and at the eutectic composition pearlite is formed from the remaining enriched austenite.
Fe, C 1.3 (wt%) steel, annealed at 1100°C
An example of a hypereutectoid steel (one that has a carbon composition above that of the eutectic). Upon cooling from the austenite field, the first phase to form is cementite on the austenite grain boundaries. This partitions iron and at the eutectic composition pearlite is formed from the remaining enriched austenite.
Ordered film of carbon nanotubes
It is necessary to form a stable dispersion of nanotubes in order to properly integrate them into polymeric systems. This can be achieved by treating them with acid to oxidise the tube surfaces. The tubes will then spontaneously disperse in an aqueous medium. The viscosity of these suspensions is analogous to that of polymers; it increases gradually with concentration up to a critical point (at about 0.7vol%) where entanglement occurs. A solid nanotube film has been formed by filtering the suspe
Fracture surface in a liquid crystalline polymer
Above their melting point, liquid crystalline polymers exhibit a mesophase within which, although able to flow and are not arranged in a crystal, they exhibit long range orientational order. This molecular alignment can be exploited to make high strength and stiffness fibres such as Kevlar, or even mouldable thermotropics such as Vectra. Molecular alignment can also be controlled by an external applied field; a property exploited in liquid crystal displays. This specimen has not had a magnetic f
Hypoeutectoid steel, normalised at 950°C
A hypoeutectoid alloy (carbon composition less than eutectoid). The first phase formed upon cooling from the austenite phase field is proeutectoid ferrite. Due to the lower solubility of carbon in ferrite, carbon is partitioned into the remaining austenite. At the eutectoid point the remaining carbon enriched austenite transforms to pearlite (a mixture of ferrite and cementite) which is the darker region of the micrograph. The proportion of pearlite is dependent upon the overall composition. The
Hypoeutectoid steel, normalised at 950°C
A hypoeutectoid alloy (carbon composition less than eutectoid). The first phase formed upon cooling from the austenite phase field is proeutectoid ferrite. Due to the lower solubility of carbon in ferrite, carbon is partitioned into the remaining austenite. At the eutectoid point the remaining carbon enriched austenite transforms to pearlite (a mixture of ferrite and cementite) which is the darker region of the micrograph. The proportion of pearlite is dependent upon the overall composition. The
As-cast wrought-grade aluminium alloy
The micrograph shows Al-Mg-Fe-Si containing < 1wt.% of each solute. Addition of TiB2 particles facilitates the formation of a fine, equiaxed grain structure (grain refinement). This micrograph illustrates one of the possible growth morphologies that a solidifying metal can adopt (c.f. micrograph 711). The grains in this structure exhibit no dendritic branching, i.e. the solid-liquid interfaces of the growing grains are smooth. When a solid grain is growing from the liquid phase, it will initiall
