Disclosed herein is a high-temperature lead-free Au—Sn—Ag-based solder alloy that is excellent in sealability, joint reliability, and wet-spreadability, that can be kept at a high quality level for a long period of time, and that is provided at a relatively low cost. The lead-free Au—Sn—Ag-based solder alloy contains 27.5 mass % or more but less than 33.0 mass % of Sn, 8.0 mass % or more but 14.5 mass % or less of Ag, and a balance being Au except for elements inevitably contained therein during production. When having a plate- or sheet-like shape, the Au—Sn—Ag-based solder alloy has a surface whose L*, a*, and b* in an L*a*b* color system in accordance with JIS Z8781-4 are 41.1 or more but 57.1 or less, −1.48 or more but 0.52 or less, and −4.8 or more but 9.2 or less, respectively. When having a ball-like shape, the Au—Sn—Ag-based solder alloy has a surface whose L*, a*, and b* are 63.9 or more but 75.9 or less, 0.05 or more but 0.65 or less, and 1.3 or more but 11.3 or less, respectively.

The disclosed method relates to manufacturing a heat exchanger which causes no brazing defects, and a heat exchanger manufactured by the method. The method relates to manufacturing a heat exchanger having an aluminum alloy tube defining a cooling-medium flowing passage and a copper alloy tube defining a water flowing passage, wherein a heat exchange is carried out between a cooling medium flowing through the cooling-medium flowing passage and water flowing through the water flowing passage. The aluminum alloy tube and the copper alloy tube are brazed to each other at a temperature of less than 548° C.

An aluminum wire body, in which an aluminum or aluminum alloy electric wire and a metal to be joined are joined by solder, wherein the solder includes an oxide glass including vanadium and a conducting particle. Preferably, the conducting particle contained in the solder is 90% by volume or less and the oxide glass is 20% by volume to 90% by volume. Further preferably, the oxide glass includes 40% by mass or more of Ag.sub.2O in terms of oxides and the glass transition point is 180° C. or less.

A multi-layered brazing sheet material including an aluminium core alloy layer, a brazing clad layer material on one face of the core layer, an inter-layer between the core layer and brazing clad layer material, and a water-side layer on the other face of the core layer. The core layer made from aluminium alloy having, in wt. %, up to 0.6% Si, up to 0.45% Fe, 0.6% to 1.25% Cu, 0.6% to 1.4% Mn, 0.08% to 0.4% Mg, up to 0.2% Cr, up to 0.25% Zr, up to 0.2% Ti, up to 0.3% Zn, balance aluminium and impurities. The brazing layer made from aluminium alloy having 6% to 14% Si and up to 2% Mg, balance aluminium and impurities. The inter-layer made from 1xxx-series aluminium alloy. The water-side layer made from 3xxx-series aluminium alloy having 0.5% to 1.8% Mn and 1% to 3.5% Zn.

A nickel braze alloy may include less than about 2.0 wt. % aluminum, about 18.0-23.0 wt. % cobalt, about 12.0-15.0 wt. % chromium, about 3.8-4.5 wt. % molybdenum, about 0.8-1.5 wt. % niobium, about 1.8-3.0 wt. % tantalum, less than about 2.0 wt. % titanium, about 2.0-3.5 wt. % tungsten, about 0.8-1.2 wt. % boron, about 0.02-0.10 wt. % carbon, about 0.03-0.06 wt. % zirconium, and a balance of nickel and minor amounts of impurities.

The invention relates to an ingot consisting of an aluminium solder alloy having in percentage by weight 4.5%≦Si≦12%; and optionally one or more of the following alloying constituents in percentage by weight: Ti≦0.2%, Fe≦0.8%, Cu≦0.3%, Mn≦0.10%, Mg≦2.0%, Zn_23 0.20%, Cr≦0.05%, with the remainder aluminium and unavoidable impurities, individually at most 0.05 wt %, in total at most 0.15 wt %, wherein boron is additionally provided as an alloying constituent, wherein the boron content is at least 100 ppm and the aluminium alloy is free from primary Si particles having a size of more than 20 μm. The invention further relates to an aluminium alloy product consisting of an aluminium alloy, to an ingot consisting of an aluminium alloy and to a method for producing an aluminium alloy.

Disclosed is a method of brazing articles together to form at least one braze defined by complementarily curved faying surfaces on the articles, the faying surfaces each having at least one region of curvature comprising at least one point from which the surface curves in more than one direction, the method comprising the steps of: a) disposing between the complementarily curved faying surfaces at least one amorphous brazing alloy preform of complementary curvature at least in part to said at least one region of the complementarily curved faying surfaces to conform to the complementarily curved faying surfaces in said region; and b) heating the articles and at least one amorphous brazing alloy preform to a brazing temperature at which the amorphous brazing alloy flows and brazes. and brazing alloy preforms for use in such methods. Methods of forming an article comprising a curved surface from a sheet of an amorphous metal alloy are disclosed, by applying heat from a fluid to a sheet of the amorphous metal alloy to raise at least a portion of the sheet to a temperature above the glass transition temperature T.sub.g and below the crystallization temperature T.sub.x.

This disclosure includes the description of a braze alloy composition. The braze composition contains nickel, about 5% by weight to about 25% by weight germanium; and about 1% by weight to about 4% by weight boron. The composition has an amorphous structure, and is free of silicon.

An active braze alloy composition is described, including nickel; or a combination of nickel and cobalt; about 2% by weight to about 30% by weight germanium; and about 1% by weight to about 5% by weight boron and about 0.5% by weight to about 5% by weight of at least active element. The composition is free of silicon. Braze alloy joints formed of the braze alloy composition, and located in various devices, structures, and machines, are also described. A related method for repairing a crack or other cavity within a metal component, using the braze composition, is further described.

A method of preparing aluminum metal pieces for welding, along with welded sheet metal assemblies formed from the prepared aluminum metal pieces. In one embodiment, a scanning beam of a laser is directed at an edge portion of the sheet metal piece such that a portion of the scanning beam is configured to impact an oxide layer at the edge portion. The laser is pulsed in a series of ablating pulses at the edge portion, with the ablating pulses creating an ablation plume that includes ablated material from the oxide layer of the primary surface and the peripheral surface of the edge portion. The ablation plume is analyzed, and ablation and analyzing continues until a threshold of at least one constituent in the ablation plume or the analysis plume is met or exceeded. One or more operating parameters of the laser are adjusted based on the analysis of the ablation plume or analysis plume. In some embodiments, two aluminum metal pieces are simultaneously prepared.