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Questions and Answers
What does a higher working temperature do to dislocations?
What does a higher working temperature do to dislocations?
How does cryogenic deformation impact dynamic recovery?
How does cryogenic deformation impact dynamic recovery?
What effect does alloying with Mg have on dynamic recovery in Al?
What effect does alloying with Mg have on dynamic recovery in Al?
What process restores pre-deformation properties in Al alloys?
What process restores pre-deformation properties in Al alloys?
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What initiates the formation of Guinier-Preston (GP) zones in Al-Cu system?
What initiates the formation of Guinier-Preston (GP) zones in Al-Cu system?
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What does the first digit in the alloy designation define?
What does the first digit in the alloy designation define?
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Which suffix letter indicates that the aluminum alloy has undergone cold working (strain hardening)?
Which suffix letter indicates that the aluminum alloy has undergone cold working (strain hardening)?
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In the NHT family of alloys, what is a common characteristic of the compositions?
In the NHT family of alloys, what is a common characteristic of the compositions?
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What does the second digit in the alloy designation indicate?
What does the second digit in the alloy designation indicate?
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Approximately what percentage of rolled aluminum products are made from non-heat-treatable alloys?
Approximately what percentage of rolled aluminum products are made from non-heat-treatable alloys?
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Why is aluminium resistant to corrosion?
Why is aluminium resistant to corrosion?
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What effect does copper have on the corrosion resistance of Al-Cu alloys?
What effect does copper have on the corrosion resistance of Al-Cu alloys?
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How does anodising protect aluminium from corrosion?
How does anodising protect aluminium from corrosion?
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What type of alloys exhibit the most corrosion resistance?
What type of alloys exhibit the most corrosion resistance?
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Why are wrought aluminium products less susceptible to localised attack?
Why are wrought aluminium products less susceptible to localised attack?
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Which defect is characterized by large isolated voids?
Which defect is characterized by large isolated voids?
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What is the phenomenon known as 'hot tearing' a result of?
What is the phenomenon known as 'hot tearing' a result of?
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Which alloy type has the greatest resistance to hot tearing?
Which alloy type has the greatest resistance to hot tearing?
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What can result in the formation of bubbles that freeze as pores in casting processes?
What can result in the formation of bubbles that freeze as pores in casting processes?
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Where are porosity defects usually concentrated in moulds to minimize harm?
Where are porosity defects usually concentrated in moulds to minimize harm?
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What is the current emphasis in developing superplastic behavior in aluminium alloys?
What is the current emphasis in developing superplastic behavior in aluminium alloys?
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Why are forming strain rates very low in superplastic aluminium alloys?
Why are forming strain rates very low in superplastic aluminium alloys?
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What is the main reason for the increasing ratio of cast aluminium to wrought in applications?
What is the main reason for the increasing ratio of cast aluminium to wrought in applications?
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Which type of casting uses recycled stock and typically has more impurities?
Which type of casting uses recycled stock and typically has more impurities?
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What are the most common systems for cast aluminum alloys?
What are the most common systems for cast aluminum alloys?
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Study Notes
- Cold working temperature significantly impacts resulting strength by affecting the rate of dynamic recovery processes
- Cryogenic deformation slows dynamic recovery, leading to increased strength at the expense of ductility
- Alloying, such as with Mg in Al-5%Mg, can improve strain hardening and slow down dynamic recovery compared to pure Al
- Annealing at elevated temperatures can restore pre-deformation properties of Al alloys partially or fully
- Age hardening process involves solution heat treatment, rapid quenching, and controlled decomposition to form precipitates in aluminum-copper system
- Non heat-treatable alloys do not respond to strengthening by heat treatment and include pure aluminum grades and alloys with Mn or Mg as main alloying elements
- Aluminum is resistant to corrosion due to a protective oxide film, but can undergo galvanic corrosion when in contact with electrolytes and less reactive metals
- Anodizing aluminum can further protect it from corrosion by increasing the thickness of the protective oxide film through an electrolyte bath process
- Wrought aluminum products include sheet/plate, foil, wire, and tube/rods, with complex extrusions produced from cast ingots
- Porosity in aluminum castings can result from entrapped gases, volume shrinkage, and hot tearing during solidification
- Hot tearing in castings occurs due to high stresses during solidification, more susceptible in alloys with wide freezing ranges or low eutectic fractions
- Superplastic behavior is exhibited by some aluminum systems, like 5083 SPF, but has limited applications and high cost
- Cast aluminum products are increasingly used, especially in the automotive industry, with common systems being Al-Si, Al-Si-Mg, and Al-Si-Cu
- The ratio of cast aluminum to wrought aluminum is increasing, with 70% of aluminum castings in Western Europe used in the automotive sector
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Description
Explore the relationship between cold working temperature and resulting strength in materials science. Learn how cryogenic deformation affects dynamic recovery processes and the trade-off between strength and ductility. Discover how alloying can improve strain hardening for enhanced material properties.
