DOI: 10.18503/1995-2732-2022-20-3-111-121
Abstract
The article presents the experimental study on the effect of a phase composition on micro- and nanocrack formation in the near-surface layer of a single(-Ti and -Ti)- and two-phase (+) titanium alloys after wire-cut electrical discharge machining on Sodick VZ300L machine. A comparative analysis performed during the study on cracking in single-phase titanium alloys, insufficiently described in literature, with the well-studied crack formation in two-phase titanium alloys determines the relevance of this study. Scientific novelty of the study consists in the absence of a qualitative and quantitative impact of the phase composition on cracking in the near-surface layer of titanium alloys VT3-1, VT5 and VT6, established by optical, scanning and transmission electron microscopy. Practical relevance of the achieved results lies in establishing the preferred orientation, as well as the characteristic sizes of microcracks and mainline nanocracks in the near-surface layer of VT3-1, VT5 and VT6 titanium alloys after electrical discharge machining in 1, 2, 3 and 4 passes, being 20, 12, 7 and 1 µm, respectively. The achieved results are the basis for recommendations for selecting a surface finishing method: the defective «white layer» is proposed to be removed by mechanical or electrochemical treatment. To completely remove the network of microcracks, it is recommended to take off an allowance exceeding the penetration depth of microcracks by twice or higher: for the first pass is 40 µm, for the second one is 25 µm, for the third one is 15 µm and for the fourth one is 2 µm.
Keywords
titanium alloys, phase composition, nanocracks, microcracks, near-surface layer, electrical discharge machining
For citation
Fedorov A.A., Polonyankin D.A., Bredgauer Iu.O., Zhdanova Iu.E., Linovsky A.V., Bobkov N.V. Effect of a Phase Composition on Nano- and Microcrack Formation in the Near-Surface Layer of Titanium Alloys after Electrical Dis-charge Machining. Vestnik Magnitogorskogo Gosudarstvennogo Tekhnicheskogo Universiteta im. G.I. Nosova [Vestnik of Nosov Magnitogorsk State Technical University]. 2022, vol. 20, no. 3, pp. 111-121. https://doi.org/10.18503/1995-2732-2022-20-3-111-121
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