The mechanical properties and oxidation behavior were studied at various temperatures using 304L-and 310-type sintered materials prepared of water-atomized stainless steel powders, mainly in relation to press-sintering conditions and Si-addition in the range 1-4%.
The results were summarized as follows:
(1) Tensile strength was almost proportional directly to the density of sintered materials and toughness was exponential to that all over the temperatures below 900°C, where the latter was varied under appreciable influence of pore-morphology even at higher temperature.
(2) Tensile strength and toughness were simultaneously able to be improved for higher Si-content, because of δ-ferrite which promoted sinterability and of resultant α/γ duplex structures in sintered materials. On the other hand, creep-rupture strength decreased at prolonged time to 700°C, while a fairly higher value was obtained in a 310L-0.4%C specimen (AIC HK 40).
(3) Ductility and toughness were more deteriorated for 304L and 310L sintered materials exposed to air at 900°C, and less for higher Si-content because of less internal oxidation rate.
Oxidation resistance was improved for larger size of particles, lower porosity, higher sintering temperature.

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In order to study fundamentally the influences of oxygen on the properties of TiC-base cermets, the phase relationships of the Ni-Ti-O system, which is a part of the four ternary systems constituting the Ni-Ti-C-O quaternary system, were determined at 1000°C (in a solid state) and at about 2000°C (in a liquid state) mainly in the region of less than 50 at % Ti.
Even in the molten state at 2000°C or above, the oxide-metal phase separation was observed over a wide composition range, and the mutual solubility scarcely changed with temperature. At 1000°C, a nickel solid solution (γ-phase) was in equilibrium with Ti₂O₃, Ti₃O₅, Magneli phases, TiO₂, NiTiO₃ and NiO in turn as the titanium content decreased. The solubility of oxygen in the γ-phase was minimum at about 4 at% Ti.

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The microstructural features and mechanical, thermal and cutting properties of Ti(C, N)-30Mo₂C-13Ni alloys were investigated in relation to the N/(C+N) ratio.
The results obtained are as follows:
(1) The growth rate of (Ti, Mo) (C, N) phase formed around Ti(C, N) core particles decreased with an increase of N/(C+N) ratio.
(2) Hardness of sintered alloy decreased, while transverse rupture strength remained unchanged with an increase of N/(C+N) ratio. 0.002% offset yield stress in compressive test increased, however, plastic strain and Young's modulus decreased with an increase of N/(C+N) ratio.
(3) Thermal expansion coefficient and thermal conductivity increased with the rise of N/(C+N) ratio. Thermal shock resistance calculated from the equation of R=(ρσB/δE) increased with the rise of N/(C+N) ratio of the alloy.
(4) Flank wear resistance of Ti(C, N)-30Mo₂C-13Ni alloy in continuous cutting steel decreased, whereas the crater wear resistance increased with the rise of N/(C+N) ratio of the alloy. Resistance against mechanical and thermal shock of the above alloy in intermittent cutting of steel increased with the rise of N/(C+N) ratio. The alloy with N/(C+N) ratio of 0.297 was found to be the most excellent alloy in wear and shock resistance in cutting of steel.

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The short-time (<2 hr) creep-rupture strength of WC-TiC-TaC-Co alloys was studied mainly at 900-1000°C as a function of composition of WC-TiC-TaC triple carbide (βt). It was found that the creep-rupture strength of βt-Co and WC-βt-Co alloys increased with decreasing TaC content in βt, that is, steady-state creep rate dropped and the formation of stable microcracks was retarded. It was suggested that the creeprupture strength of those alloys was largely affected by βt/βt interface-strength which increased with decreasing TaC content.

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Experiments were carried out to obtain the optimum condition for preparing anisotropic Ca-La-Nd ferrite magnets having the best magnetic and physical properties. The best composition was pursued according to the formula {(100-X)(CaO·6Fe₂O₃)} {X(70%La₂O₃)}, varring X from 1.0 to 13 wt%. The samples used in this experiment were prepared by mixing of the raw materials of a-Fe₂O₃, CaCO₃, and 70% La₂O₃ (contains 20% Nd₂O₃) powder. The optimum condition of making magnets and some properties of atypical specimen are as follows. The preparation condition: composition of {92(CaO·6Fe₂O₃)8(70%La₂O₃)}, prefiring condition of 1225°C for 1 h in O₂ gas and sintering condition of 1250°C for 0.5h in O₂ gas. Magnetic and physical properties.: 4πI10k=4100G, 4πIr=3900G, IHc=1800 Oe, BHH=1760 Oe, (BH)max=3.6 MG·Oe, Ku=3.3×10₆ erg/cc, HA=20.0 kOe, as=65.0 emu/g, Tc=451°C and D=5.07 g/cc.

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