塑性变形对WC-Co硬质合金中Σ2晶界分布的影响(英文)

Effects of plastic deformation on Σ2 grain boundary distribution in WC-Co cemented carbide

在同等工艺条件下制备了两个WC-8Co试样,其中一个经历了塑性变形处理,分别收集了两个试样表面的电子背散射衍射数据。像质图样显示塑性变形破坏了WC的架状结构。分别通过取向差角分布关系、取向差角-轴分布关系和单一截面五参数法分析了Σ2晶界(即90°/[1010]晶界)的分布情况。结果显示塑性变形过程将降低Σ2晶界的分布强度。通过单一截面五参数法,解析了Σ2晶界组分对材料性能影响的权重。Σ2晶界对材料性能的影响主要通过晶界的迁移性,具体表现为晶界的滑移机制和对粘结相渗透的抵抗力。相比Σ2倾斜晶界,Σ2扭转晶界对材料性能的影响占有优势。

Two WC-8Co samples were prepared under the same conditions. One of them was treated with plastic deformation, and electron backscattered diffraction （EBSD） data were collected on the sample surfacel area, respectively. Image quality （IQ） maps showed that after deformation the WC skeleton structure hadbroken up. The distribution of E2 （90°/[ 1010] ） grain boundaries was investigated through misorientation angle distribution relationship, the axis-angle space distribution relationship, and a stereological analysis by five-parameter method from planar section. The results showed that E2 boundaries might be annihilated in the process of plastic deformation. The impact weight of E2 components to the materials performance was identified by five-parameter method, it is∑2 twist boundaries rather than ∑2 tilt boundaries that contribute to the materials properties though the mobility of grain boundaries, in the form of sliding mechanism and infiltration resistance to binder phase.