Scholarlink

<p>Laser additive repair of high-value components often involves filling geometrically complex defects, where repair quality is dictated by a unique interplay between process parameters and physical constraints. This study investigates the laser-directed energy deposition (L-DED) repair of IN718 superalloy within a pre-fabricated trapezoidal groove, a configuration that imposes severe multi-directional heat transfer and mechanical restraint. Through coupled thermo-mechanical simulations and multi-scale characterization, we reveal how laser power (400–800&#xa0;W) modulates the competing effects of the groove’s geometry. The groove geometry inherently promotes rapid cooling but also induces high residual stresses at the repair interface. At low power (400&#xa0;W), insufficient energy input combined with high geometric restraint leads to lack-of-fusion defects and interfacial fracture. Conversely, at high power (800 W), excessive thermal accumulation overwhelms the rapid cooling effect, causing grain coarsening and Laves phase segregation, resulting in brittle intergranular fracture within the deposit. An optimal power of 600&#xa0;W balances these competing factors, achieving a fine-grained microstructure with minimal defects, leading to a repair zone stronger than the substrate itself. This work elucidates the fundamental mechanisms governing repair in constrained geometries, providing a critical framework for process optimization beyond conventional flat-plate depositions.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Microstructure and mechanical properties evolution of laser additive repairing for IN718 superalloy under geometric constraints of trapezoidal groove

  • 期刊论文

  • 发表日期：

    2026年7月6日

查看全文
  • Yitong Wang,
  • Zeqi Hu,
  • Mingzhang Chen,
  • Rui Song,
  • Lin Hua,
  • Yudong Chen

摘要

Laser additive repair of high-value components often involves filling geometrically complex defects, where repair quality is dictated by a unique interplay between process parameters and physical constraints. This study investigates the laser-directed energy deposition (L-DED) repair of IN718 superalloy within a pre-fabricated trapezoidal groove, a configuration that imposes severe multi-directional heat transfer and mechanical restraint. Through coupled thermo-mechanical simulations and multi-scale characterization, we reveal how laser power (400–800 W) modulates the competing effects of the groove’s geometry. The groove geometry inherently promotes rapid cooling but also induces high residual stresses at the repair interface. At low power (400 W), insufficient energy input combined with high geometric restraint leads to lack-of-fusion defects and interfacial fracture. Conversely, at high power (800 W), excessive thermal accumulation overwhelms the rapid cooling effect, causing grain coarsening and Laves phase segregation, resulting in brittle intergranular fracture within the deposit. An optimal power of 600 W balances these competing factors, achieving a fine-grained microstructure with minimal defects, leading to a repair zone stronger than the substrate itself. This work elucidates the fundamental mechanisms governing repair in constrained geometries, providing a critical framework for process optimization beyond conventional flat-plate depositions.