Microstructure and mechanical properties of SiCp/AZ91 composite processed with extrusion and EPT

Abstract

By hot extrusion at 250°C and electrical pulse treatment (EPT) of 40 μs duration and 10 min processing time, a homogeneous matrix microstructure with an average grain size of 0.91 μm and abundant Mg₁₇Al₁₂ phase was obtained in SiCp/AZ91 magnesium matrix composite. Moreover, SiCp were helpful to promote the accumulation of crystal defects and the precipitation of Mg₁₇Al₁₂ phase. After extrusion at 250°C, the yield strength (YS) and ultimate tensile strength (UTS) of the composite reached 480 and 556 MPa, respectively. With the increase of the duration and the processing time, the YS and UTS of SiCp/AZ91 composite were reduced due to the softening effect of static recrystallisation but its tensile elongation to failure (TEF) was improved slightly.

KEYWORDS:

• SiCp/AZ91 magnesium matrix composite
• hot extrusion
• electrical pulse treatment
• static recrystallisation
• mechanical properties

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China under Grant [number U1710118, U1810122, 51504162 and 51601123], Outstanding Innovative Teams of Higher Learning Institutions of Shanxi under Grant [number 2018], and Shanxi Scholarship Council of China under Grant [number 2016-029].