February AMP_Digital

A D V A N C E D M A T E R I A L S & P R O C E S S E S | F E B R U A R Y / M A R C H 2 0 1 9 1 8 • 2124 Al alloy +25% SiC (0.3 µm particle size): 2.88 g/cm 3 density (AMC225XF) Al-SiC composite powder (pre- pared by high speed attrition milling) was supplied by Materion Inc. Discs were sintered from the pow- ders at about 550°C and 45 MPa for 25 minutes. Sintering was completed within 5 minutes. All sintered prod- ucts exhibited >99% of theoretical density. Sintering parameters were ad- justed using step heating to minimize the temperature gradient for manufac- turing larger discs (5 in. diameter by 1 in. thick; 125 mm diameter by 25 mm thick) weighing 1193 grams. Sinter- ing was complete within 20 minutes at sintering temperatures as shown in a typical sintering plot (Fig. 3). The total processing cycle lasted approximately 100 minutes. Using the same sintering process window, 20 discs of each composition were produced with a density >99% of theoretical. These discs were used as feedstock material for extrusion in (a) (b) Fig. 2 — (a) FAST R&D unit with 25 ton capacity; (b) R&D unit with 250 ton capacity (inset: sintering chamber with graphite die); and (c) hybrid R&D unit with 325 ton capacity. (c) Fig. 3 — Sintering plot in fabricating 5-in. diameter by 1-in. thick Al-40 vol% SiC composite discs.