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AssigneeSumitomo Electric Industries, Ltd.
InventorsTsuyoshi Asai, Naoji Fujimori, Takaharu Yamamoto
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This invention relates to a hard alloy consisting of a metallic phase and a hard phase having a B1 type crystal structure, and being represented by the following general formula, (M.sub.1a, M.sub.2b, M.sub.3c)(C.sub.1-x-y N.sub.y O.sub.x).sub.z in which M.sub.1 is at least one of Group IVa elements, M.sub.2 is at least one of Group VIa elements, M.sub.3 is at least one of Group Va elements, C is carbon, N is nitrogen, O is oxygen, a, b, c, x and y are respectively atomic ratios satisfying the relations of a+b+c=1, 0.1.ltoreq.(a+c)/a+b+c).ltoreq.0.7 (c can be zero), 0.05.ltoreq.x.ltoreq.0.5, 0.ltoreq.y.ltoreq.0.5, 0.05.ltoreq.x+y.ltoreq.0.6 and z is an atomic ratio of (C+N+O)/M.sub.1 +M.sub.2 +M.sub.3) satisfying the relation of 0.1.ltoreq.z.ltoreq.0.5.
A sintered hard alloy consisting of a metallic phase and a hard phase having a B1 type crystal structure and being represented by the following general formula:
A sintered hard alloy consisting of a metallic phase and a hard phase having a B1 type crystal structure and being represented by the following general formula:
A process for producing a sintered hard alloy represented by the following general formula:
Dependencies are inferred from the claim text.
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No related US applications are recorded in the indexed filing history.
Alloys based on carbides, oxides, nitrides, borides, or silicides
Alloys
Term ended 22 Sep 1998 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The present invention relates to a hard alloy and a process for the production thereof and more particularly, it is concerned with a hard alloy with a high melting point metal binder, which is excellent in toughness.
2. Description of the Prior Art
The accompanying drawing is to illustrate the principle and merits of the present invention and shows an X-ray diffraction pattern of an alloy of the present invention having a composition of (Ti.sub.0.33 W.sub.0.67)(C.sub.0.8 O.sub.0.2).sub.0.33, 1 being peaks of W and 2 being peaks of TiC phase.
We, the inventors, have made detailed studies on alloys of this type, in particular, elements for forming the hard phase and consequently, have found surprisingly that the sintering property of a hard alloy is markedly improved and, moreover, the toughness thereof is also improved by introducing into the hard phase oxygen which has hitherto been considered to be detrimental to sintering of the hard alloy. Based on this finding, the present invention provides a hard alloy with a high melting point binder, excellent in toughness, as a tool with a high efficiency.
The most important feature of the present invention consists in introducing positively oxygen into the hard phase of a hard alloy. In this alloy, oxygen is hardly introduced into the other part than the hard phase and the hard phase becomes thus one with a composition of (M.sub.1, M.sub.2)(C, O).sub.z or (M.sub.1, M.sub.2)(C, O, N).sub.z in which M.sub.1 represents one or more metals selected from Group IVa elements of Periodic Table, i.e., Ti, Zr and Hf and M.sub.2 represents one or more metal selected from Group VIa elements of Periodic Table, i.e., Cr, Mo and W. This is apparent from the accompanying drawing showing an X-ray diffraction pattern of an alloy of the present invention having a composition of (Ti.sub.0.33 W.sub.0.67)(C.sub.0.8 O.sub.0.2).sub.0.33, in which there are found W and TiC phase only. 1 is peaks of W and 2 is peaks of TiC phase. This is the same in an alloy containing N.
Oxygen is thus present in the hard phase as a solid solution element without forming any oxide. The effects or merits in the case of incorporating oxygen will be apparent from the following Examples and, in general, the alloy strength is increased and the toughness when using as a cutting tool is largely improved.