Partial melting behavior and thixoforming properties of extruded magnesium alloy AZ91 with and without addition of SiC particles with a volume fraction of 15％

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2018,（7）
• 页码范围: 1149-1161
• 页数: 13页
• 语种: 英文

摘要

A series of reheating-isothermal holding experiments and compression tests were conducted on pristine magnesium alloy AZ91 extruded by equal channel angular extrusion (ECAE) and SiC particles (a volume fraction of 15％) reinforced AZ91 composite (AZ91-SiCp) by regular extrusion.Dissolution ofeutectic compounds and partial melting of the α-Mg matrix occurred during the reheating of these materials.Spherical semisolid slurries of these materials were obtained when the reheating temperature and isothermal holding time were 550 ℃ and 20 s,respectively.The presence of SiCp in AZ91-SiCp not only caused lower liquid fractions of semisolid slurries but also resulted in higher values of flow stress during semisolid compression tests.Both AZ91 alloy and AZ91-SiCp composite exhibited better thixoforming properties at high temperatures.Segregation of SiCp did not occur during thixoforming of AZ91-SiCp composite after an isothermal holding at semisolid temperatures for 20 s.