Novel Concept of Creep Strengthening Mechanism using Grain Boundary Fe 2 Nb Laves Phase in Austenitic Heat Resistant Steel
Novel Concept of Creep Strengthening Mechanism using Grain Boundary Fe 2 Nb Laves Phase in Austenitic Heat Resistant Steel
复制标题
奥氏体耐热钢晶界Fe 2 Nb Laves相蠕变强化机制的新概念
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
M. Takeyama
中科院分区：
文献类型：
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作者：
I. Tarigan;K. Kurata;N. Takata;T. Matsuo;M. Takeyama
研究了新型奥氏体耐热钢Fe-20Cr-30Ni-2Nb （at）的蠕变行为。（%），经金属间fe2nb Laves相强化。特别注意的是晶界Laves相在长期蠕变强化机制中的作用。根据公式e/e =(1−ρ)可知，随着晶界Laves相面积分数（ρ）的增加，蠕变阻力增大，其中e0为ρ = 0时的蠕变速率。此外，蠕变断裂寿命也随着ρ的增加而延长而没有延展性损失，即使在ρ = 89%时也可以产生高达77%的延伸率。显微组织分析表明，在晶界附近无析出相，存在局部变形和发育良好的亚晶，而在晶界附近有位错堆积。因此，晶界Laves相通过阻止位错运动有效地抑制了局部变形，从而提高了长期蠕变断裂强度。这种新的蠕变强化机制被称为“晶界沉淀强化机制”（GBPS）。
The creep behavior of a new type of austenitic heat-resistant steel Fe-20Cr-30Ni-2Nb (at.%), strengthened by intermetallic Fe 2 Nb Laves phase, has been examined. Particular attention has been given to the role of grain boundary Laves phase in the strengthening mechanism during long-term creep. The creep resistance increases with increasing area fraction (ρ) of grain boundary Laves phase according to equation e/e = (1−ρ), where e 0 is the creep rate at ρ = 0. In addition, the creep rupture life is also extended with increasing ρ without ductility loss, which can yield up to 77% of elongation even at ρ = 89%. Microstructure analysis revealed local deformation and well-developed subgrains formation near the grain boundary free from precipitates, while dislocation pile-ups were observed near the grain boundary Laves phase. Thus, the grain boundary Laves phase is effective in suppressing the local deformation by preventing dislocation motion, and thereby increases the long-term creep rupture strength. This novel creep strengthening mechanism was proposed as “ grain boundary precipitation strengthening mechanism ” (GBPS).