PSI - Issue 20

Yakovleva S.P. et al. / Procedia Structural Integrity 20 (2019) 190–197 Yakovleva S.P. et al. / Structural Integrity Procedia 00 (2019) 000–000

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strength — mechanical and chemical. Increasing the hardness and strength of a two-component matrix of experimental DMC as a result of heat treatment after explosive pressing promotes the growth of the mechanical component. It is fair to assume that the interaction of diamond carbon with the material of the matrix during heating will complement the mechanical connection between them more durable chemical. This is supported by the results of micro-x-ray spectral analysis of the border zones between diamond and matrix of experimental composites (Fig. 2), in which, in addition to carbon, fairly high contents of such strong carbide-forming elements as iron and chromium are revealed by Hsieh et al. (2001), Tillmann et al. (2015), Sidorenko et al. (2013). The presence of these elements suggests that favorable conditions are created on the border between a diamond and matrix to provide chemical bonds that increase the strength and wear resistance of the obtained DMC. The solidity and strength of the diamond-matrix interphase boundaries in the experimental DMC is confirmed by the results of wear resistance tests.

Fig. 2.Microstructure of the zone between a diamond and matrix (a) and local content of chemical elements in the area bounded by the circle (b). The sample is etched.

3.4. Comparative wear resistance tests

The good prospects of using the technology combining explosive compaction and short-term annealing to obtain a DMC with a high level of operational properties was confirmed by the results of tests for the wear resistance of DMC prototypes and control diamond dressers. Comparative tests showed (Fig. 3) that the wear resistance of DMC samples corresponds to the wear resistance of industrially produced diamond dressers, but at half the consumption of diamond powder (volume fraction of diamonds in DMC - 2%, in dressers - 5%); geometrical dimensions of the AMC samples and the dressers, the characteristics of the diamond component in them are the same. As can be seen in Fig. 3, an increase in the content of the harder component P2 in the binder and an increase in the charge power makes it possible to ensure a sufficient level of wear resistance with significant savings of diamond raw material.

3.5. Mechanism of diamond particles removal at abrasive wear of experimental DMC

During the operation of diamond tools, each diamond grain is subjected to intense elastic and plastic deformation, as well as dynamic effects, which is accompanied by a high temperature in the contact zone and leads to destruction and removal of diamond particles. The features of the loss of the functional properties of diamond grains during wear of the experimental DMC were studied.