Q1: Temper brittleness of a material can be fairly detected by the __________ test.

ANS:B - notched bar impact

Temper brittleness of a material can be fairly detected by the notched bar impact test. Explanation:

1. Temper Brittleness: Temper brittleness refers to the tendency of certain materials, particularly steels, to become brittle or susceptible to fracture when subjected to specific temperature conditions, often resulting from improper heat treatment.
2. Notched Bar Impact Test: The notched bar impact test, commonly known as the Charpy or Izod impact test, is a standard test method used to evaluate the impact toughness or resistance to fracture of materials, including metals.
3. Test Procedure: In the notched bar impact test, a standardized specimen with a V-notch or U-notch is subjected to a single, sudden impact load at a specified temperature. The energy absorbed by the specimen during fracture is measured and used as an indication of its toughness.
4. Detection of Temper Brittleness: Temper brittleness can cause a material to exhibit reduced impact toughness, leading to increased susceptibility to brittle fracture during impact loading. Therefore, the notched bar impact test can effectively detect temper brittleness by assessing the material's response to impact loading at different temperatures.
5. Interpretation of Results: A material exhibiting temper brittleness will typically show a significant reduction in absorbed energy or impact toughness at temperatures associated with the onset of brittleness. This reduction in toughness can be observed in the form of lower impact energy values or brittle fracture surfaces in the tested specimens.
6. Applications: The notched bar impact test is widely used in quality control and material evaluation across various industries, including manufacturing, construction, and engineering, to assess the impact performance of materials and detect potential issues such as temper brittleness.