【摘 要】
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The novel cast irons of chemical composition (wt％) 0.7C–5W–5Mo–5V–10Cr–2.5Ti were invented with the additions of 1.6wt％ B and 2.7wt％ B. The aim of this work was to study the effect of boron on the structural state of the alloys and phase elemental distrib
【机 构】
：
Physics Department,Pryazovskyi State Technical University,Mariupol,87555,Ukraine;Mechanical Engineer
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The novel cast irons of chemical composition (wt％) 0.7C–5W–5Mo–5V–10Cr–2.5Ti were invented with the additions of 1.6wt％ B and 2.7wt％ B. The aim of this work was to study the effect of boron on the structural state of the alloys and phase elemental distribution with respect to the formation of wear-resistant structural constituents. It was found that the alloy containing 1.6wt％ B was composed of three eu-tectics: (a) “M2(C,B)5+ferrite” having a “Chinese Script” morphology (89.8vol％), (b) “M7(C,B)3+Austenite” having a “Rosette” morphology, and (c) “M3C+Austenite” having a “Ledeburite”-shaped morphology (2.7vol％). With 2.7wt％ of boron content, the bulk hardness increased from HRC 31 to HRC 38.5. The primary carboborides M2(C,B)5 with average microhardness of HV 2797 appeared in the structure with a volume fraction of 17.6vol％. The volume fraction of eutectics (a) and (b, c) decreased to 71.2vol％ and 3.9vol％, respectively. The matrix was“ferrite/austenite” for 1.6wt％ B and “ferrite/pearlite” for 2.7wt％ B. Both cast irons contained compact precipitates of carbide (Ti,M)C and car-boboride (Ti,M)(C,В) with a volume fraction of 7.3％–7.5％. Based on the energy-dispersive X-ray spectroscopy, the elemental phase distribu-tions and the appropriate phase formulas are presented in this work.
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