Diffusion and homogenization in “iron (5 μm–nickel (5 μm or 50 nm)” powder systems of various degrees of dispersion during sintering (900 and 1000°C), as well as spark plasma sintering, are investigated using the Matano–Boltzmann method. Calculated diffusivities in pairs of micron powders sintering without applying pressure (900°C, 6 h) and by the spark plasma method (900°C, 5 min) in these systems are equal to 7 × 10^–10 cm²/s. It is shown that the use of nanodispersed nickel powder in diffusion pairs based on finely dispersed iron powder promotes a twofold increase in diffusivity at 900°C in contrast to the pair with the microdispersed nickel powder. Constants in the Ivensen sintering kinetics equation are calculated for the “iron–nickel” powder systems, by which the factors activating sintering of these systems are established. The dependences of the structural phase composition and physicomechanical properties of carbide steels of the Fe(base)–14 wt % Ni–8 wt % TiC system on the sintering temperature in range t = 900–1200°C and structure dispersity and homogeneity are determined. The dependences of the grain size, porosity, hardness, microhardness, fracture toughness, and bending ultimate strength on the sintering temperature are shown. Dependences of tribotechnical properties on the degree of homogeneity of the solid solution and volume of the phase transformation of metastable austenite into deformation martensite during abrasive friction turn out similar for carbide steels and diamond tools based on carbide steel. Optimal values of the variation coefficient of the nickel concentration in austenite and carbide steels of the same chemical composition but with different degrees of dispersity, which provide the maximal volume of the austenite decomposition and high values of the diamond-tool grinding coefficient, turn out equal to 5 in both systems, but the sintering parameters are different. It is shown that the physicomechanical properties of the studied systems depend on the structure porosity and dispersity, while tribotechnical properties depend on the structural homogeneity of steels.

中文翻译：

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结构分散和均匀性对粉末亚稳奥氏体硬质合金钢和金刚石工具性能的影响

使用Matano–Boltzmann研究了在烧结（900和1000°C）以及火花等离子烧结过程中不同程度分散的“铁（5μm-镍（5μm或50 nm）”粉末系统中）的扩散和均质化在这些系统中，不施加压力（900°C，6 h）和通过火花等离子体法（900°C，5 min）烧结成对的微米级粉末对的计算扩散率等于7×10 ^–10 cm ²/ s。结果表明，与微分散的镍粉相比，在基于细分散的铁粉的扩散对中使用纳米分散的镍粉可促进900°C扩散系数的两倍增长。计算出“铁-镍”粉末体系的伊文森烧结动力学方程中的常数，由此确定了激活这些体系的烧结因素。Fe（基）–14 wt％Ni–8 wt％TiC系统的碳化物钢的结构相组成和物理力学性能与t范围内的烧结温度有关= 900–1200°C，并确定结构的分散性和均匀性。示出了晶粒尺寸，孔隙率，硬度，显微硬度，断裂韧性和弯曲极限强度与烧结温度的关系。对于硬质合金钢和基于硬质合金钢的金刚石工具来说，摩擦学性质对固溶均匀度和亚稳态奥氏体到变形马氏体相变量的依赖关系类似。化学成分相同但具有不同分散度的奥氏体和碳化钢中镍浓度变化系数的最优值，可以提供最大的奥氏体分解量和高的金刚石刀具磨削系数值在两个系统中都减至5 但烧结参数不同。结果表明，所研究体系的物理力学性能取决于结构的孔隙率和分散性，而摩擦学性能则取决于钢的结构均匀性。