Dissociation of a ⟨100⟩ edge superdislocations in the γ ′-phase of nickel-base superalloys
Dissociation of a ⟨100⟩ edge superdislocations in the γ ′-phase of nickel-base superalloys
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DOI：
10.1080/14786430600796551
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发表时间：
2006-08
影响因子：
1.6
通讯作者：
Christopher Kohler;T. Link;A. Epishin
中科院分区：
文献类型：
--
作者：
Christopher Kohler;T. Link;A. Epishin
采用分子动力学模拟和弹性力学理论研究了Ni3Al中α 100刃超位错的解离。结果表明，当位错接近于011取向时，位错的解离既可以是对称的，也可以是不对称的。对称解离，称为Hirth锁，具有最低的能量。解离的原因是由于核分裂和解离区内弹性应变的松弛引起的能量的强烈降低。在高温合金的γ′筏中，α 100刃超位错的解离是它们沿α 011刃取向排列的原因。然而，解离并不阻碍位错的运动，因为它们通过攀爬穿透γ′筏。在高温（≥1000°C）下镍基高温合金蠕变试验的典型载荷条件下，Hirth锁会略微膨胀，但保持稳定。非对称构型的稳定性较差，可以转变为较低能量的Hirth锁。
Dissociation of a⟨100⟩ edge superdislocations in Ni3Al, the hardening γ′-phase of nickel-base superalloys, was investigated using molecular dynamics simulations and theory of elasticity. It was shown that these dislocations dissociate either symmetrically or asymmetrically when they are close to the ⟨011⟩ orientation. The symmetric dissociation, called Hirth lock, has the lowest energy. The reasons for the dissociation are the strong energy reduction due to the core splitting and the relaxation of elastic strains within the dissociation area. The dissociation of a⟨100⟩ edge superdislocations is the reason for their alignment in ⟨011⟩ orientation in the γ′-rafts of superalloys. However, the dissociation does not block the movement of the dislocation because they penetrate the γ′-rafts by climbing. Under loading conditions, typical for creep tests of nickel-base superalloys at high temperatures (≥1000°C), the Hirth lock slightly expands but remains stable. The asymmetric configuration is less stable and can transform into the lower energy Hirth lock.