粉末预处理和合金固溶对SPS烧结Ti(CN)基金属陶瓷的影响

Effects of Powders' Pretreatment and Alloy-Dissolution on Ti(CN)-Based Cermets Sintered by SPS

采用粉末真空脱氧处理、SPS烧结、合金固溶处理制备Ti(CN)基金属陶瓷。用XRD、SEM等分析烧结体的物相、显微组织、断口形貌。结果表明:通过对原料粉末在800℃下进行2h真空脱氧处理可降低金属陶瓷的孔隙率和增加WC固溶,使抗弯强度从482MPa提高到655MPa。在1250℃对SPS烧结后的金属陶瓷进行45min真空固溶处理,其抗弯强度提高到1250MPa,但是如果温度继续升高至1300℃,由于包覆相的厚度增加,抗弯强度降低。分析发现:高的抗弯强度主要源于环形相的形成和孔隙率的进一步降低。

Ti（CN）-based cermets were fabricated by powers＇ pretreatment, SPS and alloy-dissolution. The phase, microstructure and fracture surfaces of the samples were studied by X-ray diffraction analysis（XRD） and scanning electron microscopy（SEM）. It was found that porosity of metal cermets was reduced and dissolution of WC was improved by power＇s pretreatment in vacuum; the traverse strength was increased from 482 MPa to 655 MPa. After alloy-dissolved at 1250 ℃ holding 45 min, Ti（CN）-based cermets＇ traverse strength increased to 1250 MPa, but when the temperature increased to 1300 ℃, the traverse strength decreased because of thick rim phase. According to the analysis of the microstructure, it was found that the high traverse strength was owing to the appearance of core/rim structure and reduction of porosity.