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<p>Chromium (Cr)-modified titanium disilicide (TiSi<sub>2</sub>) alloys containing 0 − 10 wt% Cr were synthesized by spark plasma sintering (SPS) to investigate the effect of Cr addition on silicide phase evolution, microstructural development, and high-temperature oxidation behavior. Increasing Cr content during SPS progressively transformed the TiSi<sub>2</sub> matrix into a multi-silicide system comprising Cr<sub>0.2</sub>Si<sub>2</sub>Ti<sub>0.8</sub>, CrSi<sub>2</sub>, and Cr<sub>3</sub>Si<sub>5</sub>Ti<sub>3</sub>, indicating a strong chemical affinity between Cr and Si under the applied processing conditions. At moderate Cr levels (≤ 5 wt%), enhanced densification and mechanical performance were observed, with the highest relative density (98.07%) and hardness (1015 HV) at 5 wt% Cr. In contrast, a further increase in Cr content to 10 wt% promoted the formation of coarse Cr-rich regions and increased porosity, thereby reducing hardness. Cyclic oxidation tests conducted at 1100&#xa0;°C for eight cycles revealed a clear composition-dependent oxidation response. Alloys containing ≥ 5 wt% Cr exhibited around a 76% reduction in mass gain with suppressed spallation after 8 cycles. Cross-sectional SEM–EDX, TEM, HRTEM, and STEM–EDX analyses reveal the formation of Cr<sub>2</sub>O<sub>3</sub>-enriched interfacial regions located beneath the outer TiO<sub>2</sub>–SiO<sub>2</sub>-based oxide scale. These Cr<sub>2</sub>O<sub>3</sub>-rich interfacial zones function as a transitional barrier, thereby enhancing oxidation resistance, improving oxide-scale adhesion, and promoting interfacial stability. This study successfully decouples the effects of alloy chemistry from processing-induced variations through the rapid SPS consolidation. The findings demonstrate that 5 wt% Cr-modified TiSi<sub>2</sub> is a promising candidate for high-temperature structural component applications, where lightweight and oxidation-resistant materials are paramount.</p>

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Phase evolution during spark plasma sintering and cyclic oxidation behavior of Cr-modified TiSi2 alloys

  • 期刊论文

  • 发表日期：

    2026年4月1日

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  • Toto Sudiro,
  • Syafian F. Bilbusyra,
  • Andi Suhandi,
  • Oman Zuas,
  • Fadli Rohman,
  • Resetiana Dwi Desiati,
  • Bambang Hermanto,
  • Ponky Ivo,
  • Rahadian Roberto,
  • Sovian Aritonang,
  • Arif Tjahjono

摘要

Chromium (Cr)-modified titanium disilicide (TiSi2) alloys containing 0 − 10 wt% Cr were synthesized by spark plasma sintering (SPS) to investigate the effect of Cr addition on silicide phase evolution, microstructural development, and high-temperature oxidation behavior. Increasing Cr content during SPS progressively transformed the TiSi2 matrix into a multi-silicide system comprising Cr0.2Si2Ti0.8, CrSi2, and Cr3Si5Ti3, indicating a strong chemical affinity between Cr and Si under the applied processing conditions. At moderate Cr levels (≤ 5 wt%), enhanced densification and mechanical performance were observed, with the highest relative density (98.07%) and hardness (1015 HV) at 5 wt% Cr. In contrast, a further increase in Cr content to 10 wt% promoted the formation of coarse Cr-rich regions and increased porosity, thereby reducing hardness. Cyclic oxidation tests conducted at 1100 °C for eight cycles revealed a clear composition-dependent oxidation response. Alloys containing ≥ 5 wt% Cr exhibited around a 76% reduction in mass gain with suppressed spallation after 8 cycles. Cross-sectional SEM–EDX, TEM, HRTEM, and STEM–EDX analyses reveal the formation of Cr2O3-enriched interfacial regions located beneath the outer TiO2–SiO2-based oxide scale. These Cr2O3-rich interfacial zones function as a transitional barrier, thereby enhancing oxidation resistance, improving oxide-scale adhesion, and promoting interfacial stability. This study successfully decouples the effects of alloy chemistry from processing-induced variations through the rapid SPS consolidation. The findings demonstrate that 5 wt% Cr-modified TiSi2 is a promising candidate for high-temperature structural component applications, where lightweight and oxidation-resistant materials are paramount.