Fe, C 0.9 (wt%) steel, hypereutectoid, 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 0.9 (wt%) steel, hypereutectoid, 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.
Fe, C 2, Mn 0.7 (wt%) steel, quenched, producing martensite and cracking
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. This phase is unable to accommodate volume changes plastically and may therefore fail, nucleating cracks as seen in this sample. The different colours in the micrograph are an artefact of the etching process.
Fe, C 2, Mn 0.7 (wt%) steel, quenched, producing martensite and cracking
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. This phase is unable to accommodate volume changes plastically and may therefore fail, nucleating cracks as seen in this sample. The different colours in the micrograph are an artefact of the etching process.
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.
Fe, C 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.
Fe, C 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.
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 0.3 (wt%) steel, spheroidised carbide
A hypoeutectoid alloy (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 eutectic 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.Subsequent
Fe, C 0.4, Mn 0.8 (wt%) steel, normalised
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
The Role of Advanced VR Interfaces in Knowledge Management and Their Relevance to CAD
This paper introduces knowledge management and computer aided visualisation as a key in establishing both valuation and value creation capabilities in the enterprise where dissemination of knowledge and effective sharing of information through collaboration spur creativity and stimulate business practices. The paper draws an original approach for the design and development of a universal information/knowledge visualisation tool and outlines the mechanics that enable the working prototype that fo
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
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 0.1 (wt%), hypoeutectoid alloy
This is a hypoeutectoid alloy, which has been air cooled from the austenite phase field at 950 °C. The first solid to form is proeutectoid ferrite, its morphology being determined by the cooling rate. At slow cooling rates (furnace cooling) there is sufficient time for the carbon rejected from the austenite to diffuse and equilibrium solidification occurs. With faster cooling the microstructure also depends on the original austenite grain size.Fast cooling and large grain size favours ferrite f
Television Beyond Frontiers: reflections on public service broadcasting in a digital Europe
The cornerstone of European media policy, public service broadcasting has long been characterised by transitions, questioning and criticism. Now convergence, media cross-over, EU interference and new public service management theories affect its very chances of survival. Caroline Pauwels is the head of the Institute for Broadband Technologies/Studies on Media, Information and Telecommunications at the Free University of Brussels (VUB) and was appointed media commissioner by the Flemish Governmen
What has the financial crisis taught Europe?
The recent financial crisis has uncovered several weaknesses in Europe's regulatory system. Belatedly, the European Commission has tried to fix these weaknesses with extensive new regulation, including the creation of several new institutions. Simeon Djankov Deputy Prime Minister and Minister of Finance of Bulgaria will in this lecture offer an analysis of the most recent developments as well as a perspective on how the financial sector in Europe, and its regulation, will look like in the coming
Alpha Kappa, Pomona College
Women of Alpha Kappa, a debate society for women at Pomona College, pose for a photograph sitting on a large log.
