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<p>In this study, 5 wt.% SiC/7075Al composites with excellent comprehensive properties were fabricated by a powder metallurgy route consisting of spark plasma sintering (SPS), hot rolling, and high-frequency pulse current treatment. Results show that a small number of holes existed in the as-SPSed composites, and the relative density was 98.25%. Hot rolling deformation increased the relative density to 99.73%; however, it inevitably resulted in severe stress concentration and micro-crack phenomena. After high-frequency pulse current treatment, the thermal and non-thermal effects promoted the dislocation movement and static recrystallization, which increased the recrystallization ratio to 39.7% and decreased the grain size from 2.45 to 1.95&#xa0;μm. Furthermore, the elevated temperature at the tips of micro-cracks, combined with the compressive stress induced by the skin and proximity effects of high-frequency pulse current, facilitated the partial healing of these micro-cracks. Results of the nanoindentation test show that higher microhardness and lower indentation work recovery rate were obtained in the as-currented composites, which are 20% higher than that of as-rolled composites. The above research provides a new approach to the study and preparation of such composites. Under the joint action of grain refinement, precipitated strengthening, and micro-crack healing, the tensile strength, yield strength, and elongation at fracture of the as-processed composites (after current treatment at 10,000&#xa0;Hz) reached 475&#xa0;MPa, 160&#xa0;MPa, and 18.8%, respectively.</p>

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Enhanced Mechanical Properties of SiC/7075Al Composites via SPS-Rolling and High-Frequency Pulse Current Treatment

  • 期刊论文

  • 发表日期：

    2025年8月13日

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  • Xiaozhe Sun,
  • Ruifeng Liu,
  • Zhiqiang Li,
  • Xinru Li,
  • Weihao Han

摘要

In this study, 5 wt.% SiC/7075Al composites with excellent comprehensive properties were fabricated by a powder metallurgy route consisting of spark plasma sintering (SPS), hot rolling, and high-frequency pulse current treatment. Results show that a small number of holes existed in the as-SPSed composites, and the relative density was 98.25%. Hot rolling deformation increased the relative density to 99.73%; however, it inevitably resulted in severe stress concentration and micro-crack phenomena. After high-frequency pulse current treatment, the thermal and non-thermal effects promoted the dislocation movement and static recrystallization, which increased the recrystallization ratio to 39.7% and decreased the grain size from 2.45 to 1.95 μm. Furthermore, the elevated temperature at the tips of micro-cracks, combined with the compressive stress induced by the skin and proximity effects of high-frequency pulse current, facilitated the partial healing of these micro-cracks. Results of the nanoindentation test show that higher microhardness and lower indentation work recovery rate were obtained in the as-currented composites, which are 20% higher than that of as-rolled composites. The above research provides a new approach to the study and preparation of such composites. Under the joint action of grain refinement, precipitated strengthening, and micro-crack healing, the tensile strength, yield strength, and elongation at fracture of the as-processed composites (after current treatment at 10,000 Hz) reached 475 MPa, 160 MPa, and 18.8%, respectively.