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加热温度对TA10/14Cr1MoR复合板界面组织与性能的影响

Effect of heating temperature on interfacial microstructure and mechanical properties of TA10/14Cr1MoR clad plate

  • 摘要: 近年来,钛/钢复合板凭借优异的综合性能在石化领域获得广泛应用,但其轧制复合工艺窗口较窄,制约了产品的稳定化生产。为此,基于真空轧制复合技术,制备出TA10/14Cr1MoR复合板,通过电子探针(EPMA)、扫描电镜(SEM)、电子背散射衍射(EBSD)和剪切试验等手段,研究了加热温度对其复合界面的显微组织、元素扩散行为和界面结合性能的影响。结果表明,随着加热温度升高,复合界面脱碳层、界面反应层和β-Ti层的厚度均逐渐增加,其中界面反应层的产物及分布状态决定了界面的结合性能。850℃和900℃加热及随后相同轧制条件下,Fe元素在α-Ti中扩散较弱,界面仅形成TiC层,平均剪切强度分别为254 MPa和328 MPa,断裂主要发生在TA10基体中,其剪切强度差异主要与不同温度下TA10基体组织相关;而950℃加热及随后轧制时,C元素在界面富集程度降低,Fe元素与Ti元素的扩散反应加剧,导致界面产生不均匀的TiC+FeTi金属间化合物反应层,从而使剪切裂纹主要沿界面扩展发生脆性断裂,其剪切强度较低并呈现较大波动。与工业纯钛相比,TA10钛合金因具有较高的β相变温度,其复合板的加热温度可提高至900℃,同时扩大了钢基体组织性能调控工艺窗口。

     

    Abstract: In recent years, Titanium/steel clad plates have been widely utilized in the petrochemical industry due to their outstanding comprehensive properties. However, the relatively narrow roll-bonding process window constrains stable, high-quality production. Therefore, TA10/14Cr1MoR clad plates were prepared by vacuum rolling cladding technology. The effects of heating temperature on the microstructure, element diffusion behavior and interface bonding properties of TA10/14Cr1MoR clad plates were studied by means of electron probe microanalyzer(EPMA), scanning electron microscope(SEM), electron back scattering diffraction(EBSD) and shear test. The results show that the thickness of decarbonized layer, interfacial reactive layer and β-Ti layer increased with the rising of heating temperature, and the product and distribution of the interfacial reactive layer determine the interfacial bonding properties. At 850 ℃ and 900 ℃ of heating temperatures, the diffusion of Fe in α-Ti was relatively limited, resulting TiC layer at the interface, and the average shear strength was 254 MPa and 328 MPa, respectively. The fracture mainly occurred in TA10 substrate, and the discrepancy in shear strength was primarily related to the microstructure of TA10 substrate at different temperatures. At 950 ℃ of heating temperature, the concentration of the C element at the interface was reduced, and the diffusion reaction between Fe and Ti element intensifies. This results in the formation of an uneven TiC+FeTi intermetallic compounds layer at the interface, which caused brittle fracture mainly along the interface, with low shear strength and large fluctuation. Compared with commercial pure titanium, the heating temperature of TA10/steel clad plate can be increased to 900 ℃ due to its higher β phase transition temperature, and the process window for regulating the microstructure properties of steel substrate was expanded.

     

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