Deformation Twinning Versus Slip in Ni-Based Alloys, Containing Pt2Mo-Structured, Ni2Cr-Typed Precipitates
Deformation Twinning Versus Slip in Ni-Based Alloys, Containing Pt2Mo-Structured, Ni2Cr-Typed Precipitates
复制标题
DOI：
10.1016/j.matdes.2021.109820
复制
发表时间：
2021-05
影响因子：
8.4
通讯作者：
H. T. Vo;K. Dang;F. Teng;Matthew M. Schneider;B. P. Eftink;S. Maloy;J. Tucker;L. Capolungo
中科院分区：
文献类型：
--
作者：
H. T. Vo;K. Dang;F. Teng;Matthew M. Schneider;B. P. Eftink;S. Maloy;J. Tucker;L. Capolungo
镍基合金因其优异的机械性能而广泛应用于各种极端环境中。这些合金的优异强度来自于通过热时效引入的长程有序沉淀物的添加。位错和LRO沉淀物之间的相互作用决定了这些合金的变形模式和塑性响应。虽然大多数研究都集中在L12结构的沉淀强化镍基合金，很少的工作已经考虑了含有Pt2Mo结构，Ni2（Cr，Mo）型沉淀的镍基合金。在这些合金中，Pt2Mo结构的沉淀物使室温变形孪晶，除了滑移，这增加了应变硬化性从散装机械测试测量。虽然以前的几何模型表明，变形孪晶是有利于滑移，影响孪晶与滑移之间的激活的因素还没有彻底探讨在这类镍基合金。在这项工作中，分子动力学研究了可能的类型的位错和Pt2Mo结构的沉淀物在低温下的相互作用。结合内situmicromechanical测试，解决的剪切应力的作用，位错偏置直接影响激活的滑移与孪生。此外，使用基于能量的方法，分子动力学的结果表明，一种新的孪晶形成过程中，所造成的位错相互作用与Pt2Mo结构的沉淀物。
Nickel-based alloys are extensively used in a wide range of extreme environments because of their exceptional mechanical properties. The excellent strength of these alloys is derived from the addition of long-range ordered precipitates, introduced by thermal aging. The interactions between the dislocations and LRO precipitates dictate the deformation modes and plastic response in these alloys. While the majority of studies have focused on L12-structured precipitate-strengthened Ni-based alloys, less work has considered the Ni-based alloys containing Pt2Mo-structured, Ni2(Cr,Mo)-typed precipitates. In these alloys, Pt2Mo-structured precipitates enable room-temperature deformation twinning in addition to slip, which increases strain hardenability measured from bulk mechanical testing. Although previous geometric-based model suggested that deformation twinning is favored over slip, the factors that influence the activation between twinning versus slip have not been thoroughly explored in this class of Ni-based alloys. In this work, molecular dynamics examined the possible types of dislocation and Pt2Mo-structured precipitate interactions at low temperature. Combined within situmicromechanical testing, the role of resolved shear stresses on dislocation partials were shown to directly influence the activation of slip versus twinning. Additionally, using an energy-based approach, molecular dynamics results demonstrated a novel twin formation process, caused by the dislocation interaction with the Pt2Mo-structured precipitates.