Powder metallurgy (P/M) is a particularly attractive manufacturing process for titanium (Ti) components as conventional shape casting routes are not practical due to the reactivity of molten Ti with most gas atmospheres and with most materials which might serve as crucibles. This chapter discusses the conventional press-and-sinter Ti P/M process. It begins by providing a historical overview of the methods of production for Ti powder and the characteristics of the powders produced. It then reviews key issues in the cold pressing and sintering processes of Ti and its alloys.

Sintering of titanium and its alloys

Alloy powder for forming a hard phase for a valve seat material having excellent high temperature wear resistance. The overall composition is consisted of Mo: 48 to 60 mass %, Cr: 3 to 12 mass % and Si: 1 to 5 mass %, and the balance of Co and inevitable impurities.

Alloy powder for forming hard phase and ferriferous mixed powder using the same, and manufacturing method for wear resistant sintered alloy and wear resistant sintered alloy

High-speed steel powders (T42 grade) have been uniaxially cold-pressed and vacuum sintered to full density. Subsequently, the material was heat treated following an austenitising + quenching + multitempering route or alternatively austenitising + isothermal annealing. The isothermal annealing route was designed in order to attain a hardness value of ∼50 Rockwell C (HRC) (adequate for structural applications) while the multitempering parameters were selected to obtain this value and also the maximum hardening of the material (∼66 HRC). Microstructural characterisation has been carried out by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The microstructure consists of a ferrous (martensitic or ferritic) matrix with a distribution of second phase particles corresponding to nanometric and submicrometric secondary carbides precipitated during heat treatment together with primary carbides. The identification of those secondary precipitates (mainly M 3 C, M 6 C and M 23 C 6 carbides) has allowed understanding the microstructural evolution of T42 high-speed steel under different processing conditions.

Microstructural characterisation of vacuum sintered T42 powder metallurgy high-speed steel after heat treatments

A powder metal material comprises pre-alloyed iron-based powder including carbon present in an amount of 0.25 to 1.50% by weight of the pre-alloyed iron-based powder. Graphite is admixed in an amount of 0.25 to 1.50% by weight of the powder metal material. The admixed graphite includes particles finer than 200 mesh in an amount greater than 90.0% by weight of the admixed graphite. Molybdenum disulfide is admixed in an amount of 0.1 to 4.0% by weight of the powder metal material, copper is admixed in an amount of 1.0 to 5.0% by weight of the powder metal material, and the material is free of phosphorous. The powder metal material is then compacted and sintered at a temperature of 1030 to 1150° C. At least 50% of the admixed graphite of the starting powder metal material remains as free graphite after sintering.

Iron-based sintered powder metal for wear resistant applications

The present invention provides a magnesium alloy material excellent in mechanical properties without using specific manufacturing facilities and processes and a method of manufacturing the same. The magnesium alloy material is an Mg-Zn-RE alloy containing, as an essential component, Zn and at least one of Gd, Tb, and Tm as RE, and of the rest including Mg and unavoidable impurities, and has stacking faults of a thickened two-atomic layer of Zn and RE in the alloy structure of the Mg-Zn-RE alloy. A method of manufacturing a magnesium alloy material involves a casting step, a solution treatment step, and a heat treatment step and the heat treatment step is carried out in a condition satisfying -14.58[ln(x)] + 532.32 < y < -54.164[ln(x)] + 674.05 and 0 < x = 2, wherein y denotes the heat treatment temperature (K) and x denotes the heat treatment time (h).

Magnesium alloy material and method for manufacturing the same

Disclosed is a sintered valve guide guide formed of a sintered alloy consisting essentially of 3.5 to 5 % copper, 0.3 to 0.6 % tin, 0.04 to 0.15 % phosphorus, 1.5 to 2.5 % carbon and the balance iron, by mass, and as occasion needs, further containing 0.46 to 1.41 % metal oxide, and MnS and/or magnesium silicate. The metallographic structure has: a matrix containing a pearlite phase, a Fe-P-C compound phase and a Cu-Sn alloy phase; pores; and a graphite of 1.2 to 1.7 % by mass of the sintered alloy. In the cross section, the ratio of the pearlite phase to the matrix is 90 area% or more, the ratio of the Fe-P-C compound phase is 0.1 to 3 area% of the cross section, the ratio of the Cu-Sn alloy phase to the cross section is 1 to 3 % by area, and the ratio of a portion of the Fe-P-C compound phase having a thickness of 15 microns or more is 10 area% or less of the whole Fe-P-C compound phase.

Sintered valve guide and manufacturing method thereof

A wear resistant sintered member comprising an Fe base alloy matrix and a hard phase dispersed in the Fe base alloy matrix and having an alloy matrix and hard particles precipitated and dispersed in the alloy matrix. Manganese sulfide particles having particle size of 10 μm or less are uniformly dispersed in crystal grains of the overall Fe base alloy matrix, and manganese sulfide particles having particle size of 10 μm or less are dispersed in the alloy matrix of the hard phase.

Wear resistant sintered member and production method therefor

Wear resistant sintered member

A sintered valve seat includes: a matrix; 5 to 40 mass % of a hard phase dispersed in the matrix, the hard phase containing 48 to 60 mass % of Mo; 3 to 12 mass % of Cr; 1 to 5 mass % of Si; and the balance of Co and inevitable impurities; and a structure in which a Cr sulfide is dispersed around the hard phase. The hard phase is formed with a Co base alloy matrix and compounds which are mainly composed of Mo silicides and are integrally precipitated in the Co base alloy matrix.

Sintered valve seat and production method therefor

A sintered material for valve guides consists of, by mass %, 1.3 to 3% of C, 1 to 4% of Cu, 0.01 to 0.08% of P, 0.05 to 0.5% of Sn, and the balance of Fe and inevitable impurities. The sintered material exhibits a metallic structure made of pores and a matrix. The matrix is a mixed structure of a pearlite phase, a ferrite phase, an iron-phosphorus-carbon compound phase, and at least one of a copper-tin alloy phase and a combination of a copper phase and a copper-tin alloy phase. A part of the pores includes graphite that is dispersed therein. The iron-phosphorus-carbon compound phase is dispersed at 3 to 25% by area ratio, and the copper-tin alloy phase and the combination of the copper phase and the copper-tin alloy phase are dispersed at 0.5 to 3.5% by area ratio, with respect to a cross section of the metallic structure, respectively.

Hiroki Fujitsuka

Papers

Sintered valve guide and manufacturing method thereof

Wear resistant sintered member and production method therefor

Wear resistant sintered member

Sintered valve seat and production method therefor

Sintered material for valve guides and production method therefor