Abstract: An aluminum alloy for internal-combustion engine pistons has good high-temperature strength and good abrasion resistance. It comprises from 2 to 5% by weight of copper, from 13 to 16% by weight of silicon, from 0.2 to 1.3% by weight of magnesium, from 1.0 to 2.5% by weight of nickel from 0.05 to 0.2% by weight of vanadium and from 0.004 to 0.02% by weight of phosphorus, with the balance of aluminum. To produce the piston, a melt of the aluminum alloy having the defined composition is cast and then aged under heat at 220 to 260.degree. C. for 3 to 5 hours (T5 treatment) or, after having been cast, heated at 480 to 510.degree. C. for 3 to 10 hours for solution treatment and then aged under heat at 240 to 260.degree. C. for 3 to 5 hours (T6 or T7 treatment).

Abstract: The purpose of the present invention is to provide a titanium nitride aluminum based sintered material having excellent durability and able to be cheaply produced and cut spheroidal graphite cast iron at high speed and be used as a cutting tool material having a long life, and a method of production the same. The present invention resides in a production method of a titanium nitride aluminum based sintered material characterized in that powder of Ti.sub.(1-x) Al.sub.x N (x=0.05.about.0.70) is sintered. Said x is preferably set to a range from 0.05 to 0.15 or from 0.50 to 0.70. 0.2 to 11.1% of an additive by volume constructed by TiO.sub.y (y=1.about.2) and/or Al.sub.2 O.sub.3 is preferably externally added to the above titanium nitride aluminum based sintered material.

Abstract: The purpose of the present invention is to provide a cubic boron nitride based sintered material having excellent durability and capable of cutting at least spheroidal graphite cast iron at high speed and usable in a cutting tool having a long life, and a production method of this cubic boron nitride based sintered material. The present invention resides in a production method of a cubic boron nitride based sintered material characterized in that a mixing raw material is produced by mixing powder of Ti.sub.(1-x) Al.sub.x N(x=0.05.about.0.70) and the powder of a cubic boron nitride, and is next sintered. A compounding ratio of the above mixing raw material is preferably set such that this mixing raw material includes 10 to 90% of the above Ti.sub.(1-x) Al.sub.x N(x=0.05.about.0.70) by volume and 10 to 90% of the above cubic boron nitride by volume.

Abstract: A valve apparatus for prevention of a shocking torque in a clutch mechanism includes a housing having a chamber, the housing including an inlet port for being connected with the master cylinder and an outlet port for being connected with the release cylinder. A valve member is slidably disposed in the chamber to partition the chamber into a first chamber and a second member. The valve member includes a restricted passage connected to the first chamber and the second chamber when the valve member is closed. A first elastic member biases the valve member toward a closed position and a second elastic member biases the valve member in the counter direction of the biassing direction of the first elastic member. A wall member is disposed between the outlet port and the valve member for directing fluid flowing from the outlet port to the valve member.

Abstract: A composite aluminum member joining process. A chemical film including potassium and fluorine is formed on an aluminum member or a flux including potassium and fluorine is coated on an aluminum member. The coated aluminum member is buried together with a disposable pattern in a predetermined assembled state in a mold including molding sand. Then, molten aluminum alloy is poured into the mold, thereby molding an aluminum alloy cast member. The mold is decompressed through the molding sand, thereby expelling tar-like substances generated when the disposable pattern comes in contact with the molten aluminum alloy, burns and vaporizes, at least from the boundary surface between the disposable pattern and the molding sand to the molding sand disposed around the disposable pattern and preventing the tar-like substances from interposing between the aluminum member and the aluminum alloy cast member made from the molten aluminum alloy.