Fracture toughness and thermal resistance of polycrystalline diamond compacts
Fracture toughness and thermal resistance of polycrystalline diamond compacts
复制标题
DOI：
10.1016/0921-5093(95)10105-5
复制
发表时间：
1996-05
期刊：
影响因子：
6.4
通讯作者：
D. Miess;G. Rai
中科院分区：
文献类型：
--
作者：
D. Miess;G. Rai
聚晶金刚石复合体(PCD)越来越多地用于石油和天然气钻探以及陶瓷和硬质有色金属材料的加工。金刚石的平均粒度及其分布被用作调整PCD压坯性能的手段之一。金刚石烧结过程需要在金刚石粉末上放置碳化钨钴圆盘，然后在高压和高温条件下进行。在此过程中，来自碳化钨圆盘的WC-Co液体渗入到金刚石粉末中，提供了促进金刚石粒间结合的液体相。关于液态碳含量的数量和化学成分取决于金刚石的平均颗粒尺寸及其分布。较细的钻石尺寸往往比较粗的尺寸具有更高的烧结密度，这表明金属含量的体积分数更高。研究了金刚石层中残留金属含量和平均晶粒度对金刚石层断裂韧性的影响。用径向压缩试验测定了断裂韧性。金属含量较低的大颗粒PCD压坯比残余金属相含量较高的细晶材料具有更高的韧性。对不同起始直径、不同粒度的PCD压坯在不同气体环境下进行高温处理，并对其耐热性进行了测试。结合金刚石粒间结合的发展，用金刚石层的总金属含量来解释这一结果。
Polycrystalline diamond compacts (PCD) are being used increasingly for oil and gas drilling and in machining of ceramics and hard non-ferrous materials. Average diamond grain size and its distribution are used as one of the means to tailor properties of PCD compacts. The diamond sintering process requires use of a tungsten carbide cobalt disc placed onto diamond powder followed by high pressure and high temperature conditions. During this process pseudo-eutectic, WC-Co liquid from the tungsten carbide disc is infiltrated into diamond powder providing a liquid phase to facilitate inter-grain diamond bonding. The amount and chemical composition with respect to carbon content of the liquid phase are dependent on average diamond grain size and its distribution. Finer diamond sizes tend to have higher sintered density than coarser sizes indicating a higher volume fraction of metallic content. The role of residual metallic content of the diamond layer in conjunction with average grain size on fracture toughness of the diamond layer was investigated. The fracture toughness was determined using a diametral compression test. Larger grain PCD compacts having lower amounts of matallic content were found to have a higher toughness than fine grained materials with higher amounts of residual metallic phase. PCD compacts of different starting diameter grain sizes were subjected to elevated temperatures under different gas environments and examined for their thermal resistance. The results are explained in terms of total metal content of the diamond layer in conjunction with the development of inter-grain diamond bonding.