Abstract: Methods of fabricating objects using additive manufacturing are provided. The methods create in situ dispersoids within the object. The methods are used with refractory alloy powders which are pretreated to increase the oxygen content to between 500 ppm and 3000 ppm or to increase the nitrogen content to between 250 ppm and 1500 ppm. The pretreated powders are then formed into layers in an environmentally controlled chamber of an additive manufacturing machine. The environmentally controlled chamber is adjusted to have between 500 ppm and 200 ppm oxygen. The layer of pretreated powder is then exposed to a transient moving energy source for melting and solidifying the layer; and creating in situ dispersoids in the layer.

Abstract: The invention relates to a device (100) for the additive manufacture of three-dimensional workpieces, in particular a 3D metal printer, comprising a print head (1) and a device (40) for generating an inert atmosphere (22) within the print head (1) by means of a gas (55), in particular inert gas, wherein the print head (1) comprises a housing (3), a device (28) for feeding a metal (14), a piston (5), a reservoir (7) with an outlet opening (10) and an actuator device (12) for displacing the piston (5), wherein the reservoir (7) has a melt region (20) and a displacement body chamber (21) for a liquid phase (8) of the metal (14), wherein the melt region (20) adjoins the inert atmosphere (22) and is connected to the displacement body chamber (21) such that, as a result of the displacement of the piston (5), the liquid phase (8) of the metal (14) can be caused to pass through the outlet opening (10).

Abstract: When a T1-tempered aluminum alloy extrusion is subjected to plastic working and thus formed into a product, crack occurrence is prevented during plastic working, and tensile residual stress of the product is reduced to improve stress corrosion cracking resistance. A T1-tempered 7000-series aluminum alloy extrusion is heated to a temperature range of 150° C. or higher, and then subjected to plastic working within the temperature range, and then cooled, and then subjected to artificial temper aging. An integral value (F140) of (T(t)?140)2 is controlled to 5×105 (° C.2·s) or less in a section of t1?t?t2, where t is time (s) from heating start, T(t) is temperature (° C.) of the extrusion at time t, t1 is time before the extrusion reaches 140° C. in a heating step, and t2 is time before the extrusion reaches 140° C. again in a cooling step.

Abstract: A method to produce metallic beryllium spheres with high sphericity in a large quantity efficiently at a low cost is provided herein. The method of continuously producing metal beryllium spheres comprises the steps of: collecting granulated beryllium spheres produced by charging beryllium powder into a rotary kiln; classifying the collected beryllium spheres by particle size with an automatic sieve; and crushing particles of beryllium spheres of non-target diameters and mixing them with the raw material beryllium powder for reuse. The rotary kiln has a core tube the inner surface of which is coated with beryllium oxide by sintering the slurry coating of beryllium hydroxide applied after alkaline silica treatment.