Research Article
Effect of Solidification Rate and Rare Earth Metal Addition on the Microstructural Characteristics and Porosity Formation in A356 Alloy
(a) Eutectic Si particle characteristics observed in variable angle mold (small) samples of A356 alloys containing La and Ce additions |
| Alloy code | RE content | Silicon particle characteristics | Actual | Area (µm2) | Length (µm) | Aspect ratio | Density (number/mm2) | La (wt.%) | Ce (wt.%) | Average | SD | Average | SD |
| DBS | 0 | 0 | 5.990 | 7.032 | 5.957 | 7.421 | 2.671 | 8240 | D10S | 0.165 | 0 | 8.805 | 10.020 | 8.536 | 10.30 | 2.468 | 6037 | D1S | 0.356 | 0 | 6.492 | 6.958 | 6.459 | 11.70 | 2.282 | 8174 | D2S | 0.685 | 0 | 7.08 | 8.56 | 5.409 | 6.78 | 2.288 | 4201 | D3S | 1.025 | 0 | 3.211 | 5.164 | 3.101 | 5.82 | 2.221 | 10149 | D11S | 0.032 | 0.082 | 7.154 | 7.915 | 6.870 | 9.75 | 2.553 | 6307 | D4S | 0.136 | 0.185 | 6.413 | 7.472 | 6.307 | 8.53 | 2.533 | 7330 | D5S | 0.046 | 0.317 | 5.683 | 6.376 | 4.967 | 6.37 | 2.451 | 7902 | D6S | 0.089 | 1.088 | 8.105 | 9.673 | 6.094 | 9.01 | 2.367 | 6795 | D7S | 0.44 | 0.282 | 5.058 | 5.868 | 6.820 | 10.80 | 2.219 | 8331 | D8S | 0.781 | 0.877 | 5.917 | 6.754 | 7.555 | 9.96 | 2.355 | 6253 | D9S | 1.073 | 0.831 | 4.426 | 4.914 | 5.254 | 7.60 | 2.124 | 16277 |
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Note. Mold temperature: 325°C; small: angle of variable angle mold is 0°.
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(b) Eutectic Si particle characteristics observed in variable angle mold (large) samples of A356 alloys containing La and Ce additions |
| Alloy code | RE addition | Silicon particle characteristics | Actual | Area (µm2) | Length (µm) | Aspect ratio | Density (number/mm2) | La (wt.%) | Ce (wt.%) | Average | SD | Average | SD |
| DBL | 0 | 0 | 21.45 | 29.53 | 9.467 | 9.397 | 2.586 | 35521 | D10L | 0.165 | 0 | 28.48 | 36.16 | 19.38 | 10.230 | 2.275 | 2349 | D1L | 0.356 | 0 | 18.24 | 28.87 | 11.42 | 9.498 | 2.237 | 5521 | D2L | 0.685 | 0 | 24.43 | 37.46 | 15.3 | 10.95 | 2.287 | 3754 | D3L | 1.025 | 0 | 19.59 | 13.96 | 9.374 | 5.804 | 2.195 | 9446 | D11L | 0.032 | 0.082 | 16.37 | 23.23 | 12.42 | 8.741 | 2.600 | 7352 | D4L | 0.136 | 0.185 | 16.19 | 25.41 | 10.23 | 8.960 | 2.499 | 5924 | D5L | 0.046 | 0.317 | 16.09 | 28.03 | 8.752 | 9.570 | 2.367 | 5668 | D6L | 0.089 | 1.088 | 18.66 | 31.05 | 9.310 | 10.410 | 2.305 | 5236 | D7L | 0.44 | 0.282 | 11.93 | 18.95 | 12.01 | 7.605 | 2.343 | 7515 | D8L | 0.781 | 0.877 | 15.95 | 24.51 | 13.200 | 8.162 | 2.332 | 4122 | D9L | 1.073 | 0.831 | 8.20 | 12.82 | 5.880 | 5.416 | 2.185 | 12862 |
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Note. Mold temperature: 325°C; large: angle of variable angle mold is 15°.
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(c) Characteristics of eutectic Si particles in variable angle mold (large) samples of Sr-modified A356 alloys containing La and Ce additions |
| Alloy code | Addition | Silicon particle characteristics | Actual | Area (µm2) | Length (µm) | Aspect ratio | Density (number/mm2) | Sr (ppm) | La (wt.%) | Ce (wt.%) | Average | SD | Average | SD |
| DBLS | 127 | 0 | 0 | 1.765 | 3.906 | 2.161 | 2.431 | 2.061 | 64199 | D10LS | 69 | 0.165 | 0 | 2.138 | 3.930 | 2.345 | 2.378 | 1.952 | 58454 | D1LS | 109 | 0.356 | 0 | 2.385 | 5.157 | 2.494 | 2.958 | 1.974 | 42526 | D2LS | 74 | 0.685 | 0 | 4.240 | 2.470 | 2.625 | 8.348 | 2.370 | 5374 | D3LS | 74 | 1.025 | 0 | 5.775 | 2.633 | 3.815 | 4.688 | 2.262 | 18163 | D11LS | 73 | 0.033 | 0.082 | 3.549 | 6.440 | 3.207 | 3.862 | 2.114 | 38504 | D4LS | 70 | 0.136 | 0.185 | 1.876 | 3.542 | 2.165 | 2.053 | 1.937 | 55283 | D5LS | 71 | 0.046 | 0.317 | 2.524 | 4.593 | 2.565 | 2.854 | 1.906 | 49097 | D6LS | 77 | 0.089 | 1.088 | 1.885 | 4.197 | 2.155 | 2.435 | 1.927 | 61875 | D7LS | 75 | 0.44 | 0.282 | 3.119 | 5.461 | 2.931 | 3.235 | 1.927 | 36082 | D8LS | 78 | 0.781 | 0.877 | 7.421 | 12.000 | 4.937 | 5.439 | 2.184 | 17488 | D9LS | 72 | 1.073 | 0.831 | 4.622 | 7.183 | 3.840 | 4.001 | 2.151 | 26061 |
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Note. Mold temperature: 325°C; large: angle of variable angle mold is 15°.
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