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本文通过W-Re合金线材与固体碳在高温下接触后,采用光学显微镜、显微硬度计及电子探针等分析手段,研究了温度(1200℃,1300℃,1550℃)和保温时间(5～10小时)对与固体碳接触后的W-3%Re及W-25%Re合金线材显微结构的影响。实验表明,W-Re合金线材在高温下与固体碳的接触,起着类似气体渗碳的作用,但速度极为缓慢。W-Re合金线材在高温下与固体碳接触一定时间以后,碳化层显微硬度增大,而且随着接触温度的升高,它的碳含量增加,硬度也增加;在相同温度及相同保温时间条件下,W-25Re的碳化层的含量比W-3%Re线材的含碳量高,硬度也相应提高。W-Re合金线材在1200℃以上的高温下与固体碳接触5小时以上时,在光学显微镜下,就能观察到碳化层。W-3%Re在1200℃或1300℃中保温20小时,仅有单层的碳化结构及基体,而W-25%Re在1200℃,保温20小时,就出现双层碳化结构(即外碳化层与内碳化层)与基体等三种明显的层次。经电子探针分析表明,外层碳化组织为(W-Re)C_2,内层碳化组织为(W-Re)_5C_4,心部为基体。随着温度升高或含碳量增大,内层碳化组织增厚。
In this paper, the temperature (1200 ℃, 1300 ℃, 1550 ℃) and holding time (5) were studied by optical microscope, microhardness tester and electron probe after W-Re alloy wire and solid carbon were contacted at high temperature. ~ 10 hours) on the microstructures of W-3% Re and W-25% Re alloy wires after being in contact with solid carbon. Experiments show that the contact of W-Re alloy with solid carbon at high temperature plays a similar role as gas carburizing, but at a very slow rate. After the W-Re alloy contact with solid carbon at high temperature for a certain period of time, the microhardness of the carbide increases, and as the contact temperature increases, the carbon content increases and the hardness increases; at the same temperature and the same holding time Under the conditions, W-25Re carbon content than W-3% Re wire carbon content, the hardness also increased accordingly. When the W-Re alloy wire is exposed to solid carbon at a temperature of 1200 ° C or more for more than 5 hours, the carbonized layer can be observed under an optical microscope. W-3% Re was retained at 1200 ° C or 1300 ° C for 20 hours with only a single layer of carbonized structure and matrix, while W-25% Re retained at 1200 ° C for 20 hours exhibited a double-walled carbonized structure Layer and within the carbonized layer) and the matrix of three obvious levels. Electron probe analysis showed that the outer carbonized layer was (W-Re) C_2, the inner carbonized layer was (W-Re) _5C_4, and the heart was the matrix. As the temperature increases or carbon content increases, the inner layer of carbonized tissue thickening.