Study on Microstructure and Mechanical Properties of Hypereutectic Al-18Si Alloy Modified with Al-3B

• Published in: Materials Vol. 11; no. 3; p. 456
• Main Authors: Gong, Chunjie, Tu, Hao, Wu, Changjun, Wang, Jianhua, Su, Xuping
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 20.03.2018; MDPI
• Subjects: Alloys; Aluminum; Ductile fracture; Elongation; hypereutectic Al–18Si alloy; Magnetic fields; Master alloys; Mechanical properties; Microstructure; modification; Morphology; Optical properties; Silicon; United States > US; China; hypereutectic Al–18Si alloy; microstructure; modification; mechanical properties
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma11030456

An hypereutectic Al-18Si alloy was modified via an Al-3B master alloy. The effect of the added Al-3B and the modification temperature on the microstructure, tensile fracture morphologies, and mechanical properties of the alloy were investigated using an optical microscope, Image-Pro Plus 6.0, a scanning electron microscope, and a universal testing machine. The results show that the size of the primary Si and its fraction decreased at first, and then increased as an additional amount of Al-3B was added. When the added Al-3B reached 0.2 wt %, the fraction of the primary Si in the Al-18Si alloy decreased with an increase in temperature. Compared with the unmodified Al-18Si alloy, the tensile strength and elongation of the alloy modified at 850 °C with 0.2 wt % Al-3B increased by 25% and 81%, respectively. The tensile fracture of the modified Al-18Si alloy exhibited partial ductile fracture characteristics, but there were more areas with ductile characteristics compared with that of the unmodified Al-18Si alloy.