Improved creep resistance of 20Cr25NiNb heat resistant steels through grain boundary intermetallic precipitation strengthening

Shu, Ming; Zhou, Qin; Shen, Yuanhua; Zhou, Zhangjian; Wang, Pengfei; Chen, Le; Sun, Yun; Xiao, Jun

doi:10.1016/j.jmrt.2023.06.213

Cited by 4 publications

(1 citation statement)

References 32 publications

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“…Therefore, the shear strength of the joints was effectively improved. It is well known that grain boundary strengthening is an important method to impede crack propagation and improve the mechanical property of joints [27][28][29][30][31][32][33][34][35]. In addition, for p-SiO 2 joints brazed with the Ag-1.0 mol% CuO filler metal, the fluidity of the filler metal was improved and all the filler metal infiltrated into the p-SiO 2 ceramic, as shown in Figure 10c.…”

Section: The Interfacial Formation Mechanism Of P-sio2 Jointmentioning

confidence: 92%

Study on Reactive Air Brazing of p-SiO2 Ceramic with Ag-xCuO Filler Metal

Chen,

Ma,

2023

Metals

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Reactive air brazing of porous SiO2 ceramic (p-SiO2) was achieved using Ag-CuO filler metal. When brazing p-SiO2, two main problems existed. Firstly, the wettability of the Ag filler metal on the surface of p-SiO2 was poor. Secondly, the residual stress caused by the mismatch of the coefficient of thermal expansion was high in the joint. In order to solve these problems, the effects of CuO contents on the p-SiO2 brazed joint were analyzed. In a wetting experiment, the addition of CuO significantly improved the wettability of the Ag-CuO/p-SiO2 system. With the content of CuO increasing, the contact angle decreased from 90° to 0°. In addition, when the content of CuO increased to 0.5 mol%, the contact angle decreased from 90° to 52°. Then, during brazing p-SiO2 with the Ag-xCuO filler metal, the typical interfacial microstructure of the joints brazed at 1000 °C for 30 min was p-SiO2 ceramic/Ag (s,s) + SiO2 + CuO/Ag (s,s)/Ag (s,s) + SiO2 + CuO/p-SiO2 ceramic. Meanwhile, Ag-CuO infiltrated into the p-SiO2 ceramic and an infiltration layer formed. The infiltration layer was composed of Ag (s,s) + SiO2 + CuO and the infiltration layer was conductive to form a good gradient transition of the coefficient of thermal expansion (CTE). Then, the residual stress in the joint was released and the shear strength improved. In addition, with the content of CuO increasing, the depth of the infiltration layer increased. Furthermore, when the content of CuO was 0.5 mol%, the maximum shear strength of the joint was 55 MPa.

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