Grain refining performance for Al and Al–Si alloy casts by addition of equal-channel angular pressed Al–5 mass% Ti alloy

✍ Scribed by Zuogui Zhang; Shigemistu Hosoda; Ick-Soo Kim; Yoshimi Watanabe

• Publisher: Elsevier Science
• Year: 2006
• Tongue: English
• Weight: 841 KB
• Volume: 425
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2006.03.018

✦ Synopsis

This paper investigated the microstructural evolution and the grain refining performance of an Al-5 mass% Ti alloy that was fabricated by the equal-channel angular pressing (ECAP) method. The microstructures were observed by a scanning electron microscopy (SEM). Platelet-shaped Al 3 Ti particles cracked severely with repetitive ECAP passes, and the mean size of the Al 3 Ti particles decreased from 70 to 3.2 m after 15 ECAP passes. Energy dispersive X-ray spectroscopy (EDXS) and X-ray diffraction (XRD) analysis showed an Al-Ti supersaturated solid solution was formed during the ECAP process. Moreover, when the ECAPed Al-Ti alloy with the Al-Ti supersaturated solid solution was added to pure Al and Al-Si eutectic alloy melts, a better grain refining effect was obtained compared to that of the same alloy without the ECAP. It is considered that the fine Al 3 Ti particles and the Al 3 Ti precipitates from the supersaturated solid solution probably contribute to the grain refinement. The pure Al and Al-12.6 mass% Si alloy that was refined by the ECAPed Al-5 mass% Ti refiner had a high Vickers microhardness and good wear resistance. It is suggested that the ECAPed Al-5 mass% Ti alloy could become an effective refiner in commercial Al cast production.