授課老師：戴子堯 教授 碩研機械一甲 -MA 胡淳翔

前言 2 As one type of heat-treatable aluminum alloys, Al–Cu cast alloys arewidely used in transportation, aerospace and military industries owingto their excellent mechanical and physical properties. For the heat-treatable aluminum alloys, the solution heat treatment (SHT) is usually the most important stage to dissolve the second intermetallic phase into α (Al) matrix. Tpresent study is focused on the mechanism of solid-state transformation of Fe- rich intermetallics in the squeeze cast Al–5.0Cu–0.6Mn alloy with variable Fe contents during solution heat treatment.

實驗過程 3 材料溫度維持在 710 ± 5 °C 在 75 Mpa 下倒入 高 65 mm 直徑 68 mm 的模具 遇熱至 250 °C 擠製成 Φ 10 mm × 20 mm 在 538 °C 維持一 段時間進行水淬

材料成分 4

結果與討論 5 Fe-rich intermetallics of the gravity die cast alloys in as- cast condition: (a) 0.1% Fe; (b) 0.5% Fe; (c) 0.7% Fe; (d) 1.0% Fe; and (e) 1.5% Fe

FE-RICH INTERMETALLICS IN SHT CONDITION (12 H): (A) 0.1% FE; (B) 0.5% FE; (C) 0.7% FE; (D) 1.0% FE; AND (E) 1.5% FE 6

XRD PATTERNS OF THE ALLOYS AFTER SHT FOR 12 H: (A) UN-DEEP ETCHED; (B) DEEP ETCHED 7

TEM MICRO-IMAGE AND EDS OF NEW Β -FE IN THE FE10 ALLOY AFTER SHT FOR 12 H 8

SEMOBSERVATIONS OF THE TYPICAL 3-DMORPHOLOGIES OF THE FE-RICH INTERMETALLICS IN AS-CAST AND SHT FOR 12 H: (A) 0.5% FE, AS-CAST; (B) 0.5% FE, SHT;(C) 1.0% FE, AS-CAST; (D) 1.0% FE, SHT 9

3-D MORPHOLOGY OF Β -FE BY DEEP ETCHING:(A) 0.5% FE; (B) 1.0% FE 10

MICRO-IMAGE, EDS AND SADP OF Α (AL) BETWEEN Β -FE PARTICLES IN THE FE05 ALLOY 11

FE-RICH INTERMETALLICS IN SHT CONDITION FOR FE05 ALLOY: (A) 10 MIN; (B) 2 H; (C) 6 H 12

FE-RICH INTERMETALLICS IN SHT CONDITION FOR FE10 ALLOY: (A) 10 MIN; (B) 2 H; (C) 6 H 13

RELATIVE AREA PERCENT OF Β -FE WITH DIFFERENT SHT TIMES 14

結論 15 The Chinese script-like α -Fe, the Al6(FeMn) and the needle-like Al3(FeMn) phases are metastable after solution heat treatment, which change to the new copper-rich β -Fe (Al7Cu2(FeMn)) phases. The TEM and the deep etching images show that the new β -Fe phases display a cylindrical structure to minimize their surface area. The transformation of the α -Fe and Al6(FeMn) directly produces a two-phase intergrowth of the β -Fe and the α (Al) phases, the Al3(FeMn) phases will directly change into β -Fe, which consumes the Al2Cu phase in the α (Al) matrix.