Effects of Microstructures and Mechanical Properties of Ferritic Ductile Iron by Increasing Inoculation Content

Author of the article:LI Xiao1,2, HUANG Zhenghua2 , XU Chunjie1 , ZHANG Zhongming1 , LEI Yu1,2, LIU Siqi1,2, XU Tao3 , YAN

Author's Workplace：1. School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China; 2.Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application, Guangdong-Hong Kong Joint Research and Development Center on Advanced Manufacturing Technology for Light Alloys, Institute of Materials and Processing, Guangdong Academy of Sciences, Guangzhou 510650, China; 3. KaShui Technology (Huizhou) Co., Ltd., Huizhou 516083, China; 4. Dongguan EONTEC Co., Ltd., Dongguan 523662, China

Key Words：Mg-rare earth alloys; die cast; microstructure; mechanical properties; thermal conductivity; fluidity

Abstract：The as-cast and die-cast Mg-6.48La-4.87Al alloy samples were prepared. The microstructure and phase composition of the as-cast and die-cast Mg-6.48La-4.87Al alloy samples were analyzed by OM, SEM and XRD, and the mechanical properties, thermal conductivity and flow properties of the as-cast and die-cast Mg-6.48La-4.87Al alloy samples were tested at room temperature. The results show that the as-cast grain is coarse and the distribution of the second phase is not uniform. After traditional die-casting, the grains become fine and the second phase is evenly distributed. The microstructure of both samples is mainly composed of α-Mg matrix, punctate Al11La3 phase and a small amount of acicular Mg12La phase. The tensile strength, compressive strength and elongation of the as-cast samples are 157 MPa, 263 MPa and 4.0% , respectively. After die-casting, the tensile strength, compressive strength and elongation of the as-cast samples are increased to 236 MPa, 345 MPa and 4.5%, respectively, which are 63%, 31% and 13% higher than the as-cast values, respectively. At the same time, they show good flow performance. The flow length is 1 374 mm. The thermal conductivity of the as-cast sample reaches 113.2 W/(m·K), and it can still maintain a high thermal conductivity of 90.9 W/(m·K) after die-casting.