In order to obtain the superalloy with excellent properties, graphene reinforced K418 nickel base superalloy(GNPs/K418 composite) was prepared by selective laser melting technique in this study. Through systematically...In order to obtain the superalloy with excellent properties, graphene reinforced K418 nickel base superalloy(GNPs/K418 composite) was prepared by selective laser melting technique in this study. Through systematically comparing and analyzing the microstructure and mechanical property of K418 superalloy and GNPs/K418 composite, it is found that the percentage of small-diameter grain(≤ 15 μm) increased from 84% to 90%, and the max strength of grain orientation(<001>) reduce from 5.76 to 4.17 due to the addition of GNPs. And GNPs can also improve the height and the full width at the half peak of the strong diffraction peak of GNPs/K418 composite. Besides, GNPs/K418 composite is a kind of sandwiched structure, which is consist of GNPs, carbides, and K418 matrix. Therefore, the hardness of the GNPs/K418 composite is 4.1% and 6.9% higher than that of the K418 matrix in the transverse and vertical direction, respectively. The room temperature tensile strength of the GNPs/K418 composite is 9% higher than that of the K418 matrix. And the 600℃ and 900℃ tensile strengths of the GNPs/K418 composite are 7.6% and 10.4% higher than that of the K418 matrix, respectively. It is inferred that the effect of graphene on K418 matrix strengthening is mainly fine grain strengthening and Orowan strengthening. However, the elongation rate of the composite material is reduced, which is attributed to crack sprouting at the interface between the matrix and GNPs under high stress.展开更多
Kirigami is an art of paper cutting,which can be used in mechanical metamaterials,actuators,and energy absorption based on its deployable and load-deflection characteristics.Traditional cuts with zero width produce un...Kirigami is an art of paper cutting,which can be used in mechanical metamaterials,actuators,and energy absorption based on its deployable and load-deflection characteristics.Traditional cuts with zero width produce undesirable plastic deformation or even tear fracture due to stress concentration in stretching.This study proposes to enlarge the cut width into a notch flexure,which is applied to an orthogonality-cutted kirigami sheet,which buckles out of plane into a 3D configuration patterns under uniaxial tension.The use of compliant beam as the notch makes the stress distribution around the cuts more uniform in both elastic and elastoplastic regime.The experimental and numerical results show that by tuning the geometric parameters of cuts and material properties of the sheets,the trigger condition of 3D patterns can be adjusted.Potential capability of tunable phononic wave propagation in this kirigami-inspired metamaterial is demonstrated.This design methodology offers a theoretical guide for kirigami-based structures.展开更多
基金financially supported by the State Key Lab of Advanced Welding and Joining,Harbin Institute of Technology(No.AWJ-21M21)the Natural Science Basic Research Program of Shaanxi(No.2021JQ-594)the Program for Graduate Innovation Fund of Xi’an Shiyou University,China(No.YCS20213190)。
文摘In order to obtain the superalloy with excellent properties, graphene reinforced K418 nickel base superalloy(GNPs/K418 composite) was prepared by selective laser melting technique in this study. Through systematically comparing and analyzing the microstructure and mechanical property of K418 superalloy and GNPs/K418 composite, it is found that the percentage of small-diameter grain(≤ 15 μm) increased from 84% to 90%, and the max strength of grain orientation(<001>) reduce from 5.76 to 4.17 due to the addition of GNPs. And GNPs can also improve the height and the full width at the half peak of the strong diffraction peak of GNPs/K418 composite. Besides, GNPs/K418 composite is a kind of sandwiched structure, which is consist of GNPs, carbides, and K418 matrix. Therefore, the hardness of the GNPs/K418 composite is 4.1% and 6.9% higher than that of the K418 matrix in the transverse and vertical direction, respectively. The room temperature tensile strength of the GNPs/K418 composite is 9% higher than that of the K418 matrix. And the 600℃ and 900℃ tensile strengths of the GNPs/K418 composite are 7.6% and 10.4% higher than that of the K418 matrix, respectively. It is inferred that the effect of graphene on K418 matrix strengthening is mainly fine grain strengthening and Orowan strengthening. However, the elongation rate of the composite material is reduced, which is attributed to crack sprouting at the interface between the matrix and GNPs under high stress.
基金This work was supported by the XJTU joint-collaboration project in multi-disciplines[xhj032021014-03]National Key Research and Development Program of China[2019YFB1311600]+1 种基金Shanxi Key Research and Development Program[2020ZDLGY06-11]Natural Science Foundation of China[No.52075411 and U1913213].
文摘Kirigami is an art of paper cutting,which can be used in mechanical metamaterials,actuators,and energy absorption based on its deployable and load-deflection characteristics.Traditional cuts with zero width produce undesirable plastic deformation or even tear fracture due to stress concentration in stretching.This study proposes to enlarge the cut width into a notch flexure,which is applied to an orthogonality-cutted kirigami sheet,which buckles out of plane into a 3D configuration patterns under uniaxial tension.The use of compliant beam as the notch makes the stress distribution around the cuts more uniform in both elastic and elastoplastic regime.The experimental and numerical results show that by tuning the geometric parameters of cuts and material properties of the sheets,the trigger condition of 3D patterns can be adjusted.Potential capability of tunable phononic wave propagation in this kirigami-inspired metamaterial is demonstrated.This design methodology offers a theoretical guide for kirigami-based structures.
