Ni-Cr合金真空预钎焊金刚石磨粒复合节块界面微结构
Interfacial microstructure of pre-brazed diamond composite segments using Ni-Cr composite alloy
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摘要: 在Ni-Cr合金中加入A合金粉制成复合钎料,在加热温度1 050 ℃和保温时间30 min的工艺下进行金刚石磨粒的预钎焊处理试验,在加热温度810 ℃和保温时间4 min的烧结工艺下制备预钎焊磨粒复合节块. 测试预钎焊磨粒的静压强度和复合节块的抗弯强度,并分析预钎焊金刚石、复合节块的界面微结构. 结果表明,复合钎料与金刚石磨粒在预钎焊过程中形成化学结合界面,且对金刚石的热损伤较小;当磨粒浓度范围为10%~50%时,复合节块的抗弯强度均高于常规金刚石节块;预钎焊金刚石与金属胎体在烧结过程中形成冶金结合界面,复合节块界面结合强度高.Abstract: Pre-brazed diamonds were fabricated by using diamonds and Ni-Cr composite brazing alloy, which were consisted of Ni-Cr alloy and A alloy. Brazing temperature was 1 050 ℃ and the holding time was 30 min. Abrasive composite segments consisting of the pre-brazed diamonds and metal matrix were sintered at the heating temperature of 810 ℃ for the dwell time of 4 min. The static compressive strength of the pre-brazed diamonds and the bending strength of the abrasive composite segments were measured. The interfacial microstructure of the pre-brazed diamonds and the composite segments fracture surface were characterized. Results obtained show that the chemical combination interface between diamonds and Ni-Cr composite alloy was developed when pre-brazing and the thermal damage to the diamonds was greatly reduced. The bending strength of the abrasive composite segments (10%-50%) was much higher than that of the conventional segments. In the composite segments the metallurgical bonding between the pre-brazed diamonds and metal matrix was formed and the diamonds were embedded firmly.