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<p>Friction during high-temperature deformation strongly affects the flow behavior and microstructural uniformity of the TC4 alloy. In this study, hot compression tests were performed at 830–1080°C and strain rates of 0.01–10 s<sup>−1</sup> under two lubrication conditions, tantalum foil (Ta) and tantalum foil + graphite sheet (Ta + C), to investigate the effects of lubrication on friction behavior, constitutive response, and microstructure. The results show that the friction factors under Ta + C lubrication are consistently lower than those under Ta lubrication, being about 0.17–0.63 and decrease with increasing temperature for both lubricants. The flow stresses are lower than the measured values, and the deviation increases with strain. At 830–880°C, the flow stress under Ta lubrication is significantly higher than that under Ta + C lubrication, and the flow curves exhibit more pronounced DRX characteristics. At 930–1080°C, the difference in flow stress between the two lubrication conditions becomes much smaller, and the flow curves tend to stabilize after the peak, suggesting DRV-dominated softening. Peak stress-based and strain-compensated Arrhenius constitutive equations were established for the <i>α</i> + <i>β</i> and <i>β</i> phase regions under both lubrication conditions, and both models showed high predictive accuracy. The activation energy values calculated under Ta + C lubrication are consistently lower than those under Ta lubrication, indicating that the reduced friction effect allows the constitutive parameters to better reflect the intrinsic hot-deformation response of alloy. Finite-element simulations at 880°C and 1 s<sup>−1</sup> show that increasing the friction intensifies strain heterogeneity, with the equivalent strain in the specimen core being significantly higher than that near the die–specimen interface. EBSD analysis further reveals that Ta + C lubrication produces a finer and more homogeneous microstructure, whereas Ta lubrication is more likely to promote local recrystallization due to stronger friction-induced strain heterogeneity.</p>

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Deformation Behavior and Constitutive Model Modification with Friction Correction of TC4 Titanium Alloy During Hot Compression

  • 期刊论文

  • 发表日期：

    2026年7月8日

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  • Zhixin Han,
  • Wei Luo,
  • Gaoyong Lin,
  • Jie Tang,
  • Weizhong Feng,
  • Pinghui Zhang,
  • Mingzhe Zhou,
  • Huiqun Liu

摘要

Friction during high-temperature deformation strongly affects the flow behavior and microstructural uniformity of the TC4 alloy. In this study, hot compression tests were performed at 830–1080°C and strain rates of 0.01–10 s−1 under two lubrication conditions, tantalum foil (Ta) and tantalum foil + graphite sheet (Ta + C), to investigate the effects of lubrication on friction behavior, constitutive response, and microstructure. The results show that the friction factors under Ta + C lubrication are consistently lower than those under Ta lubrication, being about 0.17–0.63 and decrease with increasing temperature for both lubricants. The flow stresses are lower than the measured values, and the deviation increases with strain. At 830–880°C, the flow stress under Ta lubrication is significantly higher than that under Ta + C lubrication, and the flow curves exhibit more pronounced DRX characteristics. At 930–1080°C, the difference in flow stress between the two lubrication conditions becomes much smaller, and the flow curves tend to stabilize after the peak, suggesting DRV-dominated softening. Peak stress-based and strain-compensated Arrhenius constitutive equations were established for the α + β and β phase regions under both lubrication conditions, and both models showed high predictive accuracy. The activation energy values calculated under Ta + C lubrication are consistently lower than those under Ta lubrication, indicating that the reduced friction effect allows the constitutive parameters to better reflect the intrinsic hot-deformation response of alloy. Finite-element simulations at 880°C and 1 s−1 show that increasing the friction intensifies strain heterogeneity, with the equivalent strain in the specimen core being significantly higher than that near the die–specimen interface. EBSD analysis further reveals that Ta + C lubrication produces a finer and more homogeneous microstructure, whereas Ta lubrication is more likely to promote local recrystallization due to stronger friction-induced strain heterogeneity.