Week 1b written

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School

Arizona State University *

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Course

107

Subject

Material Science

Date

Dec 6, 2023

Type

docx

Pages

6

Uploaded by CaptainHeat457 on coursehero.com

2. Chapter 1 1. Why does a razor blade get dull (blunt)? Explain. Each of the crystals that make up a razor blade includes billions of atoms that are arranged in a precise, three-dimensional pattern. The crystal's strength comes from the bonds that hold the atoms together and keep them from moving. When a razor blade cuts through hair, it collides with it and causes the crystals to reorganize into a different shape, which causes the blade to become dull. This causes the bond to break down, which ultimately causes the razor edge to develop small dents. 2. Why is re-sharpening a razor blade a challenge? Re-sharpening a razor blade is a challenge because heat softens metal crystals. Heat can affect the hardness and temper of the blade material. When re-sharpening a razor blade, high heat may affect the blade's structure and result in unwanted modifications to its qualities. Heat may be produced during re-sharpening a blade because of friction between the blade and the sharpening instrument. The blade's hardness and temper may be impacted by localized temperature rises brought on by this heat. Too much heat might cause the blade to soften, lose its hardness, or even undergo unfavorable changes in its microstructure.
3. Explain the significance of dislocations. Include connections to malleability and melting points. Dislocations are atomic disruptions that shouldn't be there and are considered flaws in the metal crystals since they deviate from the normally ideal crystalline arrangement of the atoms. However, they are crucial because metals can alter shape thanks to dislocations. The ease with which the dislocations move is also influenced by a metal's melting point, which measures how firmly the metal atoms are held together. As a result, a metal with a low melting point is brittle, whereas one with a high melting point is stronger. Metals become softer as a result of heating because it allows dislocations to move about and reorganize themselves. 4. How was copper discovered? How was it originally made? Copper was first discovered by early humans who were experimenting with various rocks and minerals in prehistoric times. Malachite was placed into a hot fire surrounded by red-hot embers in order to detect copper. The somewhat greenish rock changed into a bright metal object. Other rocks were attempted, but not all of them were successful. Early metalsmiths refined the method of producing copper through trial and error. 5. What is an alloy? Compare properties of alloys with pure metals. Explain the differences.
Alloy is the process of combining different metals to produce a new element with enhanced qualities compared to pure metals. Because the alloy atoms differ in size and chemistry from the host metal's atoms, they cause a variety of mechanical and electrical disturbances inside the host crystal that all add up to one very important thing: they make it harder for dislocations to move. This is why alloys tend to be stronger than pure metals. Additionally, if dislocations find it difficult to shift, the metal is stronger since the metal crystals have a tougher time changing shape. Thus, the magic of alloy design is to stop dislocations from moving. 6. What is steel? Steel is an alloy of iron, carbon, and other elements. Our ancestors were unaware that steel was an alloy and that carbon, in the form of charcoal, could penetrate the iron crystals as well as be used to heat and reshape iron. Steel's carbon content can be regulated during the manufacturing process, giving rise to several types and grades of steel with unique properties. It is an extensively used material in many different sectors and applications because of its excellent strength, toughness, and adaptability. 7. What is the source of carbon in steel? Charcoal is the source of the carbon in steel. Since it was a popular fuel source and produced a lot of heat, charcoal was employed in the furnaces because of its high carbon content. However, there was little control over how much charcoal was used and how it interacted with the iron or steel that was being produced. The carbon content of charcoal produced from various kinds of wood or under various circumstances may vary. This could lead to variable carbon levels in the steel produced, together with the lack of exact control over the input of charcoal.
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