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Właściwości fizyczne, mechaniczne i tribologiczne osnowy w spiekanych narzędziach metaliczno-diamentowych otrzymanych metodami HP i SPS

Bączek E.

Mechanik

2018

R. 91, nr 10

846--849

Przedstawiono wyniki badań właściwości fizycznych, mechanicznych i tribologicznych materiałów, stanowiących osnowę w spiekanych narzędziach metaliczno-diamentowych otrzymanych metodami SPS (spark plasma sintering) i HP (hot pressing). Mielone proszki na bazie żelaza skonsolidowano do gęstości względnej powyżej 97% w temperaturze 900°C, pod ciśnieniem 35 MPa i w czasie 3 min. Otrzymane spieki badano również pod kątem odporności na zużycie ścierne w obecności trzech i dwóch ciał. Wykazano, że materiały otrzymane metodą HP charakteryzują się wyższą gęstością, twardością oraz odpornością na zużycie ścierne w porównaniu z materiałami otrzymanymi metodą SPS.

Metal matrix composites were prepared by hot pressing (HP) and spark plasma sintering (SPS) techniques. Ball-milled ironbase powders were consolidated to near full density by these methods at 900°C. The physical and mechanical properties of the resulting composites were investigated. The specimens were tested for resistance to both 3-body and 2-body abrasion. The composites obtained by HP method (at 900°C/35 MPa) had higher density, hardness and resistance to abrasion than those obtained by SPS method.

Functionally graded cermets

Jaworska L., Rozmus M., Królicka B., Twardowska A.

Journal of Achievements in Materials and Manufacturing Engineering

2006

Vol. 17, nr 1-2

73--76

Purpose: Cermets have very good plasticity and high hardness. Functionally graded cermets secure obtaining of cutting tools with hard wear resistance surface layer and ductile body frame. A new FGM was obtained using P/M method. Design/methodology/approach: Materials were obtained using free sintering at vacuum and the high temperature-high pressure sintering method. Functionally graded cermets have more amount of hard phase in the surface layer and lower participation of this phase in the body frame. FGMs were prepared by the layers pressing method and the centrifugal deposition method. Findings: Material with 55 wt.% of TiC and 45 wt.% of (Ni,Mo) was prepared. The phase’s composition of this material was analysed. The ring structure of material and complex carbides formation was confirmed. The gradient of the phase composition and hardness measurement are presented. Phase composition of FGM strongly depend on conditions of centrifugal sedimentation process: duration, rotation speed, solid content, dispersive liquids. The centrifugal deposition process of powders forming guarantees gradient phase composition for materials obtaining the powder metallurgy methods. The FGM obtained by powders forming method should be sintered using pressure processes in a closed containers (or special assembly) because of materials high porosity which is a result of various chemical contents of this same material parts. Practical implications: Due to their low chemical affinity to steel and the resistance for high temperatures oxidation, cermets have better cutting properties than carbides. Application of cermet inserts guarantees the high quality of machined surface (low roughness). Cermets could be used in “dry cutting” processes. Originality/value: The centrifugal deposition method for powders with phases content gradient forming is original value.