梯度结构Mg-Gd-Y合金的变形行为及增韧机制
Deformation Behaviors and Toughening Mechanisms of Gradient-Structured Mg-Gd-Y Alloy.
作者信息
Gao Bosong, Wu Minghui, Ning Jiangli, Wang Siwei, Wang Yang
机构信息
Innovation Center for New Materials and Processing Technology, Ningbo Institute of Dalian University of Technology, Ningbo 315000, China.
North China Aluminium New Material Technology Co., Ltd., Baoding 072750, China.
出版信息
Materials (Basel). 2025 Aug 14;18(16):3818. doi: 10.3390/ma18163818.
A Mg-Gd-Y alloy prepared by surface mechanical attrition treatment (SMAT) was annealed at 450 °C combined with peak aging. The deformation and fracture mechanisms were investigated using in situ tensile tests. Through quantitative calculations of the geometrically necessary dislocation (GND) densities, it was found that the fine-grained (FG) layer in the gradient structure carried greater plastic strain than the coarse-grained (CG) layer during tension. The calculation results of the geometric compatibility parameter (m') and microstructure characterization during in situ tests showed that crack initiation and propagation were prone to occur between adjacent coarse grains. However, the hetero-deformation-induced (HDI) strengthening and strain hardening induced by the strain gradient between the FG and CG layers effectively improved the strength-ductility synergy of the gradient-structured (GS) alloy. In addition, the synergistic effect of intrinsic and extrinsic toughening mechanisms in the GS alloy played a significant role in delaying premature failure.
通过表面机械研磨处理（SMAT）制备的Mg-Gd-Y合金在450°C下进行退火并结合峰值时效处理。采用原位拉伸试验研究了其变形和断裂机制。通过对几何必需位错（GND）密度的定量计算发现，梯度结构中的细晶（FG）层在拉伸过程中比粗晶（CG）层承受更大的塑性应变。原位试验期间几何相容性参数（m'）的计算结果和微观结构表征表明，裂纹萌生和扩展易于在相邻粗晶粒之间发生。然而，FG层和CG层之间由应变梯度引起的异质变形诱导（HDI）强化和应变硬化有效地改善了梯度结构（GS）合金的强度-延展性协同效应。此外，GS合金中固有和外在增韧机制的协同效应在延迟过早失效方面发挥了重要作用。
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