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Science Interpretation of Data Q27
Passage V

A molten alloy (a mixture of 2 or more metallic elements) can be poured into a cylindrical mold and cooled to form an ingot. Crystals form inside the ingot as it cools. The average crystal length, L, in micrometers (μm), determines how brittle the ingot will be. A method for reducing L using rotating magnetic fields was applied to Alloy Q as it cooled in the molds. Table 1 shows the elemental composition of Alloy Q. Figure 1 shows the effect of the relative magnetic stirring force, F, on L for ingots formed from molten Alloy Q that had an initial temperature of either 280°C or 550°C. Table 1 Percent by mass in Element Symbol Alloy Q Aluminum Al 88.7 Silicon Si 10.8 Manganese Mn 0.28 Magnesium Mg 0.22 Figure 1 102 Key 100 280°C 550°C ) 96 m ( L 94 0 10 20 30 40 50 F ( × 10 ) Figure 1 is adapted from S. Denisov, et al., “The Effect of Traveling and Rotating Magnetic Fields on the Structure of Aluminum Alloy During Its Crystallization in a Cylindrical Crucible.” ©2014 by Institute of Physics, University of Latvia.

The following table lists the mass of silicon in 50 g samples of 4 different alloys, one of which is Alloy Q. Mass of Si Sample (g) W 0.11 X 0.14 Y 2.7 Z 5.4 Given the composition of Alloy Q, which sample is most likely Alloy Q?

  1. A

    Sample W

  2. B

    Sample X

  3. C

    Sample Y

  4. D

    Sample Z

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