1.
1XX.X designation is given to ___________ type of aluminium alloys.
Correct Answer
B. Cast
Explanation
The correct answer is "Cast." The 1XX.X designation is given to cast type of aluminum alloys. This designation system is used to classify and identify different types of aluminum alloys based on their composition and properties. The cast type alloys are specifically designated with the 1XX.X series, indicating that they are cast aluminum alloys.
2.
Which of these is unused in 4-digit designation of aluminium alloys?
Correct Answer
D. 6XX.X
Explanation
The 4-digit designation system for aluminum alloys is used to classify different alloys based on their composition and properties. The first digit represents the main alloying element or group of elements, while the second and third digits indicate the specific alloy within that group. The "6XX.X" designation is not used in this system, suggesting that there are no specific aluminum alloys classified under this category.
3.
A1 is the type of age hardenable alloys where:
Correct Answer
A. Both the temperatures of the quench bath and the aging process are above the GP solvus
Explanation
A1 is the type of age hardenable alloys where both the temperatures of the quench bath and the aging process are above the GP solvus. This means that the quench bath temperature and the aging process temperature are higher than the temperature at which the GP zone dissolves. This is important because it allows for the formation and stabilization of the desired precipitates during the aging process, leading to increased strength and hardness of the alloy.
4.
Stiffness of beam is proportional to (d = thickness of the beam)
Correct Answer
C. E and d³
Explanation
The stiffness of a beam is directly proportional to the product of the modulus of elasticity (E) and the cube of the thickness (d³) of the beam. This means that as the modulus of elasticity and the thickness of the beam increase, the stiffness of the beam also increases.
5.
Iron in Al alloys is usually kept below ________ .
Correct Answer
A. 1%
Explanation
Iron is usually kept below 1% in Al alloys because iron can have negative effects on the properties of the alloy. It can decrease the ductility and corrosion resistance of the alloy, and can also lead to the formation of undesirable intermetallic compounds. Therefore, it is important to keep the iron content low in order to maintain the desired properties of the Al alloy.
6.
T10 temper represents :
Correct Answer
D. Cooled from an elevated-temperature shaping process, artificially aged, then cold worked
Explanation
The T10 temper represents a specific heat treatment process for a material. In this case, the material is first cooled from an elevated-temperature shaping process, which could involve processes like casting or forging. After cooling, the material is artificially aged, which involves subjecting it to a controlled heat treatment to improve its strength and hardness. Finally, the material is cold worked, which means it is deformed at room temperature to further enhance its mechanical properties. This sequence of steps, from cooling to artificial aging to cold working, is what defines the T10 temper.
7.
Aluminium has __________ modulus of elasticity.
Correct Answer
A. Low
Explanation
Aluminium has a low modulus of elasticity. Modulus of elasticity refers to the stiffness or rigidity of a material. A low modulus of elasticity means that aluminium is relatively flexible and can be easily bent or deformed under stress. This property makes aluminium suitable for applications where flexibility and lightness are desired, such as in the aerospace industry or in the construction of vehicles.
8.
Stress corrosion cracking is observed in ___________ alloys.
Correct Answer
C. Precipitation-hardened
Explanation
Stress corrosion cracking is a type of corrosion that occurs in certain alloys when they are exposed to a combination of tensile stress and a corrosive environment. Precipitation-hardened alloys, also known as age-hardened alloys, are alloys that have been heat-treated to achieve a high strength through the precipitation of fine particles within the material. These alloys are susceptible to stress corrosion cracking due to the presence of these fine particles, which can act as sites for crack initiation and propagation. Therefore, stress corrosion cracking is observed in precipitation-hardened alloys.
9.
During widmanstatten structure formation, new phase is formed which is characterised by:
Correct Answer
A. Needle shaped
Explanation
During widmanstatten structure formation, a new phase is formed which is characterized by needle-shaped structures. This refers to the formation of elongated crystals or grains that have a needle-like appearance. This structure is commonly observed in certain metallic alloys, particularly those that undergo a slow cooling process. The needle-shaped crystals are a result of the diffusion of atoms during the cooling process, leading to the formation of distinct microstructures.
10.
Magnesium decreases __________ of Al alloys.
Correct Answer
C. Density
Explanation
Magnesium decreases the density of Al alloys.