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本文选用钴含量25%的WC-Co硬质合金,在1 250℃,真空条件下,对合金进行淬火,并于500℃回火,研究了淬火回火热处理对WC-25%Co硬质合金组织与性能的影响。研究结果表明,经1 250℃真空淬火并于500℃回火后,合金粘结相Co中面心立方结构α-Co的含量趋近于100%,WC平均晶粒尺寸保持不变,而WC晶粒邻接度明显减小,粘结相Co中固溶的W原子数量显著提高,裂纹的萌生和扩展受到抑制,合金的韧性获得改善。热处理后合金的矫顽磁力值和钴磁降低,合金中出现了明显的细小孔洞,其密度和硬度略微降低,但是合金抗弯强度由3 300 MPa提高至3 500 MPa。
In this paper, the WC-Co cemented carbide with 25% cobalt content was used to quench the alloy under the condition of 1 250 ℃ under vacuum and to temper it at 500 ℃. The effects of quenching and tempering on the WC-25% Co cemented carbide The impact of organization and performance. The results show that the α-Co content of the centrosymmetric cubic Co in the co-binder phase approaches 100% after vacuum-quenching at 1250 ℃ and tempering at 500 ℃, while the average grain size of WC remains unchanged. The WC The degree of grain contiguity decreases obviously, the number of W atoms dissolved in the binder phase Co increases significantly, the initiation and propagation of cracks are inhibited, and the toughness of the alloy is improved. After heat treatment, the coercive force value and cobalt magnetism of the alloy decreased. The microstructure showed obvious tiny holes with slight decrease in density and hardness, but the bending strength increased from 3 300 MPa to 3 500 MPa.