摘要:
An aluminum alloy structural member is crystalline. In producing this aluminum alloy structural member, a procedure is employed which includes forming a green compact by use of aluminum alloy having an amorphous phase, and subjecting the green compact to a powder forging technique. An aluminum alloy powder exhibiting an exotherm E smaller than 20 J/g at the time of the crystallization of the amorphous phases is used. By setting the exotherm E in such a range, cracking of the green compact due to a degassing can be avoided, even if the green compact is rapidly heated in a temperature-rising or heating course.
摘要:
A connecting rod as a shaft clamping member includes a rod member and cap, each of which has mating faces at circumferentially opposite ends of a semi-circular recess and which are fastened to each other by bolts by matching the opposed mating faces to each other to define a crank pin hole by the two semi-circular recesses. The rod member and the cap are forgings formed from an aluminum alloy and simultaneously produced by forging powder preforms of the rod member and cap in a cavity having the desired shape of the connecting rod. After forging, the opposed mating faces have an infinite number of recesses and projections which are formed from the flow of the material during the forging and which are in a matched and fitted relation to each other. Thus, any misalignment between and in a direction parallel to the mating faces can be prevented to avoid the generation of a situation that only the rod member receives a stress. This achieves a prolongation in the life of the connecting rod of the aluminum alloy. The composition of the most desirable aluminum alloy includes, by weight, 7% .ltoreq.Fe
摘要:
An aluminum alloy powder or a green compact thereof is prepared, wherein: (1) the composition formula is Al.sub.100-a-b Fe.sub.a X.sub.b where a and b in atomic % are 4.0.ltoreq.a.ltoreq.6.0, 1.0.ltoreq.b.ltoreq.4.0, and where X is at least one alloy element selected from Y and Mm (mish metal); or (2) the composition formula is Al.sub.100-a-b-c Fe.sub.a Si.sub.b X.sub.c, where a, b and c in atomic % are 3.0.ltoreq.a.ltoreq.6.0, 0.5.ltoreq.b.ltoreq.3.0, and 0.5.ltoreq.c.ltoreq.3.0, and where X is at least one alloy element selected from Ti, Co, Ni, Mn and Cr, and wherein both (1) and (2) include an amorphous phase of at least 1% by volume. The aluminum alloy powder or the green compact thereof is heated at a temperature increasing at a rate of at least 80.degree. C./min. to a predetermined temperature of at least 560.degree. C. and not more than a temperature at which 10% by volume of a liquid phase is contained in the alloy powder or green compact. The aluminum alloy powder or the green compact thereof is powder forged at the predetermined temperature. As a result, an aluminum alloy superior in static strength and dynamic strength can be produced.
摘要:
In a powder forging process, a heated green compact is placed in a stationary die and subjected to a press-forging carried out mainly to reduce the thickness thereof by cooperation of the stationary die with a movable die. The press-forging is performed at two pressing steps. After placement of the green compact into the concave molding portion of the stationary die, the pressing step were carried out. Thus, it is possible to produce a forged product having a high strength and a high toughness. A heated heat insulator also may be placed in the stationary die to provide a temperature-retaining effect to the green compact before and during pressing.
摘要:
A powder preform of aluminum alloy powder is subjected to a heating treatment and then to a compacting and hardening process under a pressure to produce a structural member of aluminum alloy. The aluminum alloy powder used is one having a non-equilibrium phase which shows a calorific value C in a range of C.gtoreq.10 J/g at a temperature-increasing rate of 20 K./min in a differential scanning calorimetry. In the heating treatment, the average temperature-rising rate R.sub.2 from a heat-generation starting temperature Tx (K.) of the aluminum alloy powder to Tx+A (wherein A.gtoreq.30 K.) is R.sub.2 .ltoreq.60 K./min. Thus, the change of the non-equilibrium phase in the powder preform is uniformly performed. In addition, the average temperature-increasing rate R.sub.4 from a processing temperature Tw (K.-B) in the compacting and hardening process to Tw (wherein B.gtoreq.30 K., and Tw-B>Tx+A) is R.sub.4 .gtoreq.60 K./min. Thus, the oxidation of the powder preform is reliably prevented.
摘要:
A heat- and abrasion-resistant aluminum alloy having a grain size of the matrix of .alpha.-aluminum in the alloy not more than 1,000 nm; a grain size of an intermetallic compounds contained in the alloy of not more than 500 nm; and 0.5 to 20% by volume of ceramic particles in the range of 1.5 to 10 .mu.m in particle size and dispersed in the alloy. By this composition, the stress concentration due to the ceramic particles is reduced. Furthermore, because the powders bind well with each other, the heat resistance and abrasion resistance are compatibly improved without decreasing toughness and ductility.
摘要:
A raw material for powder metallurgy contains at least 0.5 vol % and at most 10 vol % of alumina powder of which the sieve fraction with a sieve opening of 30 .mu.m is at most 0.1 wt %, and a remaining part of aluminum alloy powder. The moisture content of the alumina powder is at most 0.15 wt. % with respect to the alumina powder. Agglomeration of particles is thereby minimized or avoided. Highly reliable raw material for powder metallurgy having superior fatigue strength, impact resistance and wear resistance can be obtained. A method of preparing such a mixed powder raw material involves air classifying the powder materials, dry ball mixing the materials, and then annealing the mixed powder.
摘要:
This invention provides a heat-resistant, high-toughness aluminum alloy which has a good balance between strength and ductility at a temperature from room temperature to around 300 degrees C. and has a high fracture toughness, a method of manufacturing the same, and engine parts. The heat-resistant, high-toughness aluminum alloy of this invention contains 10 to 16 mass. % of silicon, 1 to 3 mass % of iron, 1 to 2 mass % of nickel, 0.5 to 2 mass % in total of one or more selected from the group consisting of titanium, zirconium, chromium and vanadium, 0.6 to 3 mass % of copper, and 0.2 to 2 mass % of magnesium, the balance being essentially aluminum, and is obtained by densifying aluminum alloy powder prepared by gas atomizing. The silicon has an average grain diameter of 4 μm or less.
摘要:
A high strength and high toughness aluminum alloy is produced by crystallization of one of two aluminum alloy blanks: one having a metallographic structure with a volume fraction Vf of a mixed-phase texture consisting of an amorphous phase and an aluminum crystalline phase being equal to or more than 50% (Vf.gtoreq.50%), and the other having a metallographic structure with a volume fraction Vf of an amorphous single-phase texture being equal to or more than 50% (Vf.gtoreq.50%). The aluminum alloy is represented by a chemical formula:Al.sub.(a) X.sub.(b) Z.sub.(c) Si.sub.(d)wherein X is at least one element selected from the group consisting of Mn, Fe, Co and Ni; Z is at least one element selected from the group consisting of Zr and Ti; and each of (a), (b), (c) and (d) is defined within the following range:84 atomic %.ltoreq.(a).ltoreq.94 atomic %,4 atomic %.ltoreq.(b).ltoreq.atomic %,0.6 atomic %.ltoreq.(c).ltoreq.4 atomic %, and0.5 atomic %.ltoreq.(d).ltoreq.(b)/3.Si is present in the form of at least one of a solute atom of an aluminum solid solution and a component element of an intermetallic compound.
摘要:
A process for producing an aluminum alloy with high strength and toughness includes the steps of: preparing an alloy blank having a primary structure which is one selected from a single-phase structure comprised of a solid-solution phase, a single-phase structure comprised of an amorphous phase, and a mixed-phase structure comprised of a solid-solution phase and an amorphous phase, and subjecting the alloy blank to a thermal treatment to provide an aluminum alloy which has a secondary structure containing 20% or more by volume fraction Vf of chrysanthemum-like patterned phases each having a diameter of at most 5 .mu.m and comprising a solid-solution phase and an intermetallic compound phase arranged radiately.