烧结温度对梯度硬质合金表层组织结构和力学性能的影响  被引量:1

Effect of Sintering Temperature on Surface-Layer Microstructure and Mechanical Properties of Gradient Cemented Carbide

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作  者:李园园 邝柄瑜[1,2] 徐银超 吴镇湘 温光华 陈响明 汤爱民[1,2] Li Yuanyuan;Kuang Bingyu;Xu Yinchao;Wu Zhenxiang;Wen Guanghua;Chen Xiangming;Tang Aimin(Zhuzhou Cemented Carbide Cutting Tools Co.,Ltd.,Zhuzhou Hunan 412007;State Key Laboratory of Cemented Carbide,Zhuzhou Hunan 412007,China)

机构地区:[1]株洲钻石切削刀具股份有限公司,湖南株洲412007 [2]硬质合金国家重点实验室,湖南株洲412007

出  处:《硬质合金》2022年第3期172-181,共10页Cemented Carbides

基  金:高端制造用高精密复合涂层切削刀具技改项目-290336。

摘  要:梯度硬质合金表层组织结构的变化直接影响着CVD涂层硬质合金刀具的加工性能,而烧结温度的变化将显著影响梯度硬质合金表层和芯部组织结构。本文研究了1410、1440℃和1460℃3种烧结温度对梯度硬质合金表层(0~100μm)组织结构和力学性能的影响规律。采用SEM和EBSD对梯度硬质合金表层组织结构、梯度区和合金芯部粒度进行了分析,研究了不同温度下表层组织结构的变化对梯度硬质合金抗弯强度和显微硬度的影响。结果表明:随着温度升高,表面Co含量明显下降,梯度层厚度增加。合金硬质相(WC和立方固溶体相)晶粒度随烧结温度升高而明显长大,梯度区内WC晶粒度大于芯部WC晶粒度,并且二者差异随烧结温度的升高而加大,芯部立方固溶体的生长速度高于WC。随烧结温度的升高,合金的磁力下降了10.3%,合金的断裂韧性和抗弯强度分别提高了8.5%和7.7%,相比去除梯度层试样,3个烧结温度下保留梯度层合金试样的抗弯强度提高了7.6%~9.8%。从表面至芯部合金的显微硬度先降低至最低点后逐渐上升至接近芯部硬度,梯度层内HV最低点约为芯部HV的87%。随烧结温度的升高,梯度区和芯部的HV都呈现下降趋势。The change in the surface-layer microstructure of gradient cemented carbide directly affects the machining performance of CVD-coated cemented carbide cutting tools,and the sintering temperature significantly regulates and controls the microstructure of gradient cemented carbide in the surface layer and the core zone.This study was conducted to explore the influence laws of sintering temperature of 1410,1440℃,and 1460℃ on surface-layer(0~100μm)microstructure and mechanical properties of gradient cemented carbide.Specifically,SEM and EBSD were employed to analyze the microstructure change and grain size of the hard phase(WC or Cubic Carbide phase)in the surface layer(where is free of cubic carbide,shorted in FCC free zone)and the core zone of gradient cemented carbide.In addition,the effect of microstructure change on transverse rupture strength(TRS)and micro hardness of gradient cemented carbide was studied.The results reveal that as the sintering temperature increases,the content of Co on the surface markedly decreases,and the thickness of the FCC-free zone increases.The grain size of hard-phase in gradient cemented carbide grows drastically as the sintering temperature rising up.The growth rate of cubic solid solution is higher than that of WC in the core zone.The WC grain size in the FCC free zone is larger than that in the core zone,and the difference gap is strengthened as sintering temperature improved,The coercive force(Hc)of gradient cemented carbide is reduced by 10.3%,while the fracture toughness and TRS in the core zone are raised by 8.5% and 7.7%,respectively,and TRS sees a growth of 9.8% due to the FCC free zone.Moreover,micro hardness in the FCC free zone first decreases to its lowest and then climbs to approach the hardness in the core zone,and the Vickers hardness(HV)at the minimum is 87% of HV in the core zone,and as the sintering temperature rises,the HV in the FCC-free zone and the core zone all tends to drop.

关 键 词:梯度硬质合金 晶粒度 梯度层厚度 显微硬度 断裂韧性 抗弯强度 

分 类 号:TG135.5[一般工业技术—材料科学与工程]

 

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