Microstructure and tensile properties of in situ Mg 2 Si p /AM60B composite prepared by thixoforging technology
- PDF / 1,396,665 Bytes
- 14 Pages / 584.957 x 782.986 pts Page_size
- 4 Downloads / 160 Views
The thixoforging technology has been proved as an effective method to fabricate the in situ Mg2Sip/AM60B composite with excellent performances. The effects of reheating temperature on microstructure and tensile properties have been investigated. The results indicate that the liquid amount, the solubility of Al in a-Mg particles, and the coarsening of the a-Mg particles are changed as the reheating temperature changes, and thus the subsequent solidification behavior and plastic deformation are thereby changed. The morphology of the Mg2Si particle also varies as the reheating temperature rises owing to partial remelting operating in the edges and corners of the particles. The best ultimate tensile strength and elongation of 209 MPa and 11.9% of the thixoforged composite, which are 93 and 138% higher than the traditional permanent mold casting respectively, are obtained under the reheating temperature of 600 °C.
I. INTRODUCTION
To cope with the energy and environmental problems, magnesium alloys have been served as lightweight structural metallic materials in the field of automotive, electronic products, portable tools, sporting goods, and aerospace vehicles in the past few years,1,2 due to their light weight, excellent castability, damping capacity, machinability, and so on.3 Nevertheless, the rapid loss of the strength at elevated temperature, low wear, and creep resistance of the magnesium alloys are the critical obstacle which limits the extended applications of magnesium alloys in industry.4,5 Magnesium-based composites, which combine the properties of magnesium with ceramic characteristics, were considered likely to solve these shortcomings of magnesium alloys,6,7 and thus their importance has been recognized accumulatively. It has been developed several methods to fabricate the magnesium-based composite, such as self-propagating high temperature synthesis, mechanical alloying, reaction spontaneous infiltration, in situ synthesis, and so on.8–12 Alternatively, the in situ synthesis technology produces the desired reinforcements via reaction synthesis in melting alloy, which is proved to be effective and maneuverable so as to achieve the magnesium-based composites. The commonly used reinforcements, such as Mg2Si, TiC, TiB2, and Mg2Ni, can be obtained through this method.13–17 Among these reinforcements, Mg2Si phase is thought to be more suitable than others on Contributing Editor: Jürgen Eckert a) Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2016.69 J. Mater. Res., Vol. 31, No. 6, Mar 28, 2016
account of its high melting point, high hardness, low density, high elastic modulus, low thermal expansion coefficient, extensive source, and nontoxicity.18,19 Till now, because of its good combination of castability, low cost, and favorable mechanical properties, AM60B alloy is the most widely used commercial magnesium alloy in industry.3 Therefore, the fabrication of in situ Mg2Sip/ AM60B composite can further extend its applications. Unfortunately, the existence of porosities deteriora
Data Loading...
