Metal components subject to wear or contact fatigue in a first area, and subject to bending, axial and/or torsional stress loading in a second area comprise a surface hardened, first surface layer in the first area, and a surface compressive-stress treated, second surface layer in the second area. The second surface layer has a material hardness different from, and typically lower than, the first surface layer, and induced residual compressive stress to improve fatigue strength. Example components described include a gear, a cog, a pinion, a rack, a splined shaft, a splined coupling, a torqueing tool and a nut driving tool. A hybrid manufacturing process is described, including area-selective surface hardening combined with a process to add compressive stress to fatigue failure prone areas.

The invention provides a method and a product for manufacturing a titanium alloy dual-structure turbine disk based on partial hydrogenation, which includes the following steps: coating a glass coating on the partial surface of a titanium alloy billet where hydrogen-blocking is required, and sintering the titanium alloy billet coated with the glass coating; performing hydrogenation treatment on the titanium alloy billet, such that the hydrogen concentration at the hydrogenation-required portion reaches the predetermined level; removing the glass coating from the titanium alloy billet; preheating the titanium alloy billet, and then performing high temperature die forging in the forging dies; performing vacuum dehydrogenation treatment on the forged turbine disk to remove hydrogen element inside the forging, so that the hydrogen content is 0.015 wt. % or less.

A method of case hardening a titanium part, including placing the titanium part within a chamber; evacuating or purging the chamber; heating the titanium part placed within the chamber; introducing a gas containing cyanogen into the chamber; and exposing the titanium part placed within the chamber to the introduced gas containing cyanogen.

A balance spring intended to equip a balance of a horological movement, wherein the balance spring is made of an alloy consisting of Nb, Ti, H and possible traces of other elements selected from O, C, Fe, N, Ni, Si, Cu and Al, with the following weight percentages: a Ti content comprised between 1 and 80 wt %, a H content comprised between 0.17 and 2 wt %, a total content of all other elements of less than or equal to 0.3 wt %, the remainder to 100 wt % consisting of Nb. A manufacturing method for the balance spring is also disclosed and includes a step of thermochemically treating a blank made of a Nb and Ti alloy in an atmosphere including hydrogen so as to enrich the Nb and Ti alloy with hydrogen in interstitial form.

Systems and methods disclosed herein relate to the manufacture of metallic material with a thermal expansion coefficient in a predetermined range, comprising: deforming, a metallic material comprising a first phase and a first thermal expansion coefficient. In response to the deformation, at least some of the first phase is transformed into a second phase, wherein the second phase comprises martensite, and orienting the metallic material in at least one predetermined orientation, wherein the metallic material, subsequent to deformation, comprises a second thermal expansion coefficient, wherein the second thermal expansion coefficient is within a predetermined range, and wherein the thermal expansion is in at least one predetermined direction. In some embodiments, the metallic material comprises the second phase and is thermo-mechanically deformed to orient the grains in at least one direction.

An alpha-beta titanium-based alloy including titanium; one of 0.001-1.0 wt. % neodymium, 0.001-1.0 wt. % dysprosium, or 0.001-0.5 wt. % erbium; and at least one of aluminum, zirconium, tin, oxygen, molybdenum, vanadium, niobium, iron, and chromium present in amounts defined based on an aluminum equivalent and a molybdenum equivalent, wherein the aluminum equivalent (Al-eq) is between 0 to 7.5% and the molybdenum equivalent (Mo-eq) is between 2.7 to 47.5, and wherein the aluminum equivalent (Al-eq) and the molybdenum equivalent (Mo-eq) are defined, in weight percents, as follows:
Al-eq=(Al %)+(Zr %)/6+(Sn %)/3+10*(O %)
Mo-eq=(Mo %)+0.67*(V %)+0.33*(Nb %)+2.9*(Fe %)+1.6*(Cr %).

A nickel-titanium alloy with an average grain size of between 0.2 and 10 microns and a recoverable strain of greater than 9% is disclosed herein, in which the alloy is formed using a method which involves applying a shape set heat treatment to the nickel-titanium alloy. The heat treatment includes applying heat at a temperature between 225° C. and 350° C. for a period of time between 20 and 240 minutes.

A non-limiting embodiment of a titanium alloy comprises, in percent by weight based on total alloy weight: 5.1 to 6.5 aluminum; 1.9 to 3.2 tin; 1.8 to 3.1 zirconium; 3.3 to 5.5 molybdenum; 3.3 to 5.2 chromium; 0.08 to 0.15 oxygen; 0.03 to 0.20 silicon; 0 to 0.30 iron; titanium; and impurities. A non-limiting embodiment of the titanium alloy comprises an intentional addition of silicon in conjunction with certain other alloying additions to achieve an aluminum equivalent value of at least 6.9 and a molybdenum equivalent value of 7.4 to 12.8, which was observed to improve tensile strength at high temperatures.

A method for producing a hot-rolled titanium plate includes, [1] melting at least one part of the side surface of the titanium slab by radiating a beam or plasma toward the side surface, not toward the surface to be rolled, and thereafter causing re-solidification to form, in the side surface, a layer having grain diameter of 1.5 mm or less and a depth of 3.0 mm or more from the side surface; [2] performing a finishing process on the surface to be rolled of the titanium slab in which the layer is formed, to thereby bring a slab flatness index X to 3.0 or less; and [3] subjecting the titanium slab after the finishing process to hot rolling under a condition in which a length of an arc of contact of a roll L in a first pass of rough rolling is 230 mm or more.

An α+β titanium alloy extruded shape containing, in mass %, Al: 5.5 to 6.8%, V: 3.5 to 5.8%, and Fe: over 0 to 0.30%, the balance being Ti and impurities, the impurities amounting to a total of 0.4% or less, the alloy including an acicular microstructure in which an average prior β grain size is 250 μm or less.