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利用热力学分析Fe-Ti-B体系反应生成TiB_2的可能性,运用DSC曲线确定原位反应温度,并采用微波烧结技术原位合成TiB_2钢结硬质合金。通过光学显微镜、扫描电镜、能谱分析仪分析微波烧结温度对原位合成TiB_2钢结硬质合金组织的影响,采用显微硬度计和万能试验机对TiB_2钢结硬质合金的显微硬度及抗弯强度进行检测分析。结果表明:Fe-Ti-B体系在637.8℃即可发生原位反应,体系中反应生成物相主要为TiB_2和Fe_2B相。随着烧结温度的升高,硬质合金的密度、显微硬度和抗弯强度均先升高后降低,在1100℃时达到最大值,即相对密度、显微硬度和抗弯强度分别为97.5%、418 HV0.1和647 MPa。
The possibility of TiB_2 reaction in Fe-Ti-B system was analyzed by thermodynamics. The in-situ reaction temperature was determined by DSC curve, and TiB_2 steel bonded carbide was synthesized in-situ by microwave sintering technology. The effect of microwave sintering temperature on the microstructure of TiB_2 steel bonded carbide was analyzed by optical microscope, scanning electron microscope and energy spectrum analyzer. The microhardness and mechanical properties of TiB_2 steel bonded carbide were measured by microhardness tester and universal testing machine. Bending strength of the test analysis. The results show that the Fe-Ti-B system can react in situ at 637.8 ℃. The reaction products mainly consist of TiB_2 and Fe_2B phases. With the increase of the sintering temperature, the density, the microhardness and the bending strength of the cemented carbide firstly increased and then decreased, reaching the maximum at 1100 ℃, that is, the relative density, the microhardness and flexural strength were 97.5 %, 418 HV0.1 and 647 MPa.