MOLDED ARTICLE MADE OF A MOLYBDENUM-ALUMINUM-TITANIUM ALLOY

Abstract

The invention relates to a molded article made of a metallic molybdenum-based alloy with at least 3 wt. % up to a maximum of 8 wt. % aluminum, at least 3 wt. % up to a maximum of 6 wt. % titanium and, as the remainder, molybdenum including the usual impurities, wherein the molded article is produced directly or indirectly by means of solidification from a melt. The invention also relates to a method for producing a molded article and to the use of such a molded article.

Claims

1. A molded article made of a metallic molybdenum-based alloy with at least 3 wt. % up to a maximum of 8 wt. % aluminum, at least 3 wt. % up to a maximum of 6 wt. % titanium and, as the remainder, molybdenum and impurities associated therewith, wherein the molded article is produced directly or indirectly by means of solidification from a melt.

2. The molded article of claim 1, wherein the impurities are a maximum of 1 at % of the molybdenum-based alloy.

3. The molded article of claim 1, wherein the impurities comprise one or more of the elements zirconium, carbon, hafnium, lanthanum, yttrium, cerium, copper, rhenium, niobium, tantalum and tungsten as a main constituent.

4. The molded article of claim 1, wherein the molybdenum-based alloy has 5.30.5 wt. % aluminum and 4.70.5 wt. % titanium.

5. The molded article of claim 1, wherein the molded article is produced by means of solidifying a melt in a casting mold.

6. The molded article of claim 1, wherein the molded article is a crucible, a rod, a rod having a point for use as a crystal nucleus for crystal growing, a sheet, a plate, a pipe, a heating coil or a heater rod.

7. The molded article of claim 1, wherein the molded article has a weight of at least 10 g.

8. The molded article of claim 1, wherein the molded article comprises a cylindrical outer wall at least in certain areas.

9. The molded article of claim 1, wherein the molded article is produced by a mold casting.

10. The molded article of claim 1, wherein the molded article contains at least 85 wt. % molybdenum.

11. The molded article of claim 1, wherein the molded article contains at least 4 wt. % aluminum.

12. The molded article of claim 1, wherein the molded article contains at least 4 wt. % titanium.

13. A method for producing a molded article from a molybdenum-based alloy with 3 wt. % to 8 wt. % aluminum, 3 wt. % to 6 wt. % titanium and, as the remainder, molybdenum and impurities associated therewith, the method comprising the following chronologically successive steps: A) producing a melt consisting of 3 wt. % to 8 wt. % aluminum, 3 wt. % to 6 wt. % titanium and, as the remainder, molybdenum and impurities associated therewith, B) pouring the melt into a casting mold and solidifying the melt in the casting mold to form a molded article in the casting mold, and C) releasing the molded article thus obtained from the casting mold.

14. The method of claim 13, wherein the molded article obtained from the casting mold contains at least 85 wt. % molybdenum.

15. The method of claim 13, wherein, in step A), the melt is melted from the pure metals molybdenum, aluminum and titanium including the impurities, wherein the impurities are present in an amount of less than 1 at %.

16. The method of claim 13, further comprising D) reshaping the molded article, wherein step D) is performed after step C).

17. An iridium replacement material comprising a molded article according to claim 1.

18. An iridium replacement material comprising a molded article formed by a method according to claim 13.

19. The method of claim 16, wherein reshaping comprises one or more of deburring, cutting, rolling, drawing, polishing and milling.

Description

[0049] Exemplary embodiments of the invention are explained below with reference to a schematically depicted FIGURE, but without thereby restricting the invention.

[0050] FIG. 1 shows a schematic perspective depiction of a molded article according to the invention.

[0051] The molded article according to the exemplary embodiment in accordance with FIG. 1 is a crucible having a cylindrical outer circumference and can comprise a rotationally symmetrical form to the cylinder axis of the outer circumference. The crucible can be laterally delimited by walls 1 which can comprise a uniform thickness. The crucible can be open upwardly and comprise an opening 2 there (see FIG. 1 at the top). One end of the crucible which is opposite the opening 2 shown (at the top in FIG. 1) can be sealed with a flat, planar base plate (not visible). As a result, an interior chamber for receiving a melt can be configured in the interior of the crucible, which can be delimited laterally by the walls 1 and on the underside by the base plate.

[0052] The crucible preferably consists of 5 to 6 wt. % aluminum, 4 to 5 wt. % titanium and the remainder of molybdenum as well as the usual impurities or another molybdenum-based alloy with 3 wt. % to 8 wt. % aluminum and 3 wt. % to 6 wt. % titanium as well as the usual impurities.

[0053] The crucible can be produced from a melt by mold casting. In order to produce the melt, the metals aluminum, titanium and molybdenum can be fused and alloyed in the desired composition by inert gas pressure melting in an arc melting furnace. During this, a pressure electroslag remelting method can be applied without slag. The melt can solidify in the gravity casting die during withdrawal downwardly from the liquid, in order to form the crucible. The crucible can be produced by primary or secondary reshaping from the resulting block or can be worked by machining from the solid material.

[0054] Instead of a crucible, as shown in FIG. 1, other molded articles such as rods, heating coils and pipes can also be produced with the same method. Such molded articles can also be reshaped further following solidification from the melt. Suitable methods for this are known to and familiar to the person skilled in the art.

[0055] The features of the invention disclosed in the above description, as well as in the claims, FIGURES and exemplary embodiments, may be essential both individually and in any desired combination to the realization of the invention in its various embodiments.

LIST OF REFERENCE NUMERALS

[0056] 1 Crucible wall [0057] 2 Opening [0058] D Diameter of the crucible