2-27. 2-28. 2-29. 2-30. 2-31. 2-32. 2-33. What methods are used to join heat- treatable aluminum alloys? 1. All welding methods 2. Spot welding and riveting only 3. Fusion welding and bolting only 4. Spot welding, fusion welding, riveting, and bolting What is the greatest disadvantage in the use of titanium? 1. Strength-to-weight ratio 2. Tendency to crack when cold- worked 3. Tendency to back away from or resist the cutting edge of tools 4. Brittleness after long exposure to temperatures above 1000°F If you hold a piece of titanium against a revolving grinding wheel, what color sparks will be produced? 1. Red spark traces that end in straw colored bursts 2. White spark traces that end in straw colored bursts 3. Red spark traces that end in brilliant white bursts 4. White spark traces that end in brilliant white bursts The use of copper as a structural material is limited because of which of the following factors? 1. Cost 2. Great weight 3. High heat conductivity 4. High electrical conductivity Because copper is very ductile and malleable,    it is ideal for making electrical wire. 1. True 2. False What is the principal element added to copper to form brass? 1. Tin 2. Lead 3. Zinc 4. Aluminum Which of the following bronze alloys has high strength and great corrosion resistance but is NOT a true bronze because it contains a small amount of tin? 1. Silicon bronze 2. Manganese bronze 3. Cast aluminum bronze 4. Wrought aluminum bronze 2-34. 2-35. 2-36. 2-37. Which of the following statements regarding Monel is NOT correct? 1. Monel is classified among the tough metals 2. Monel’s base metal is nickel and its principal alloying element is copper 3. Monel’s tensile strength can be increased to a great degree by heat treatment 4. Monel is used for aircraft parts demanding both strength and resistance to corrosion If a block of aluminum weighs 6 pounds, a block of magnesium having the same dimensions would be what weight? 1. 6 pounds 2. 2 pounds 3. 8 pounds 4. 4 pounds One of the major problems with using magnesium in aircraft construction is its short supply in the world. 1. True 2. False Which of the following extinguishing agents on a magnesium fire? 1. Graphite powder 2. Carbon dioxide 3. Water 4. Foam IN ANSWERING QUESTION 2-38, 1-3 IN THE TEXTBOOK. should be used REFER TO TABLE 2-38. You are testing a piece of steel on the Brinell tester and find the diameter of the ball impression to be 2.35 mm. What is the hardness number for this material? 114 2. 124 3. 682 4. 745 2-39. Which of the following penetrators are used with the Rockwell hardness tester? 1. Flanged head and truncated cone 2. Spiral point and steel ball 3. Diamond cone and steel ball 4. Diamond tip and spiral rod 8 1.