The present invention discloses a method for coating diamond-like carbon on heads and head drums of a video cassette recorder (VCR) by physical vapor deposition-arc method, and VCR heads coated with diamond-like carbon.

An aluminum workpiece is die cast to near net shape and subsequently only finish machined such that a portion of the hard surface region remains in the aluminum and is available as a hard working surface having a desired configuration and surface finish.

An extruded structural member suitable for aerospace applications and having improved combinations of strength and toughness. The member is made from a substantially vanadium-free aluminum-based alloy consisting essentially of: about 4.85-5.3 wt. % copper, about 0.5-1.0 wt. % magnesium, about 0.4-0.8 wt. % manganese, about 0.2-0.8 wt. % silver, about 0.05-0.25 wt. % zirconium, up to about 0.1 wt. % silicon, and up to about 0.1 wt. % iron, the balance aluminum, incidental elements and impurities, the Cu:Mg ratio of said alloy being between about 5 and 9, and more preferably between about 6.0 and 7.5. The invention exhibits a typical tensile yield strength of about 77 ksi or higher at room temperature and can be forged into aircraft wheels or extruded into various other product forms for use as high speed aircraft wing members, e.g. stringers or the like.

A method of casting an aluminum base alloy to provide a cast product having improved hot crack resistance in the as-cast condition, the method comprising providing a melt of an aluminum base alloy comprised of 4 to less than 5 wt. % Cu, max. 0.1 wt. % Mn, 0.15 to 0.55 wt. % Mg, max. 0.4 wt. % Si, max. 0.2 wt. % Zn, up to 0.4 wt. % Fe, the balance comprised of aluminum, incidental elements and impurities. The dissolved Ti in the melt is maintained in the range of about 0.005 to 0.05 wt. % to improve the resistance of the alloy to hot cracking. A nucleating agent selected from the group consisting of metal carbides, aluminides and borides is added to the melt to provide an undissolved nucleating agent therein, in the range of 0.002 to 0.1 wt. % for grain refining. The alloy is solidified to provide a cast product having a grain size of less than 125 microns and free of hot cracks.

A method of casting an aluminum base alloy to provide a cast product having improved hot crack resistance in the as-cast condition, the method comprising providing a melt of an aluminum base alloy comprised of 2.0 to less than 3.5 wt. % Zn, 2.5 to less than 4 wt. % Mg, a maximum of 2 wt. % total Fe and Mn in combination, max. 0.3 wt. % Si, max. 0.6 wt. % Cu, optionally up to 0.5 wt. % Cr, dissolved Ti in the range of about 0.005 to 0.1 wt. %, and an undissolved nucleating agent in the range of about 0.002 to 0.1 wt. % for grain refining, the balance comprised of aluminum, incidental elements and impurities. A nucleating agent selected from the group consisting of metal carbides, aluminides and borides is added to the melt to provide an undissolved nucleating agent therein, in the range of 0.002 to 0.1 wt. % for grain refining. The said alloy is solidified to provide a cast product having a grain size of less than 125 microns and free of hot cracks.