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1

Complex silumins

Pietrowski S.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

101-105

EN

Purpose: The study presents the results of investigations carried out on silumins with additions of Mg, Ni, Cu, Cr, Mo and W. The silumins containing Mg, Cu and Ni are well-known and commonly used in construction of machines and equipment. Design/methodology/approach: Additions of Cr, Mo and W have not been thoroughly investigated yet. They are considered a new family of innovative cast aluminium alloys. Findings: In Al-Si systems they form silicides, like Cr3Si, Mo3Si, W3Si and intermetallic phases of Al13Cr4Si4, Al12Mo, Al12W and AlWSi. The silicides crystallise in cubic lattice of parameters similar to aluminium and silicon. Research limitations/implications: Therefore they can act as crystallisation substrates and occur as separate phases. The examinations under the microscope and X-ray microanalysis of the linear and point distribution of elements confirmed the presence of the above mentioned phases. A combination of two elements, e.g. Cr and Mo, or Cr and W, was observed to cause the formation of complex silicide layers of Mo3Si and (Cr, Mo)3Si, or Cr3Si as well as (W, Cr)3Si. Originality/value: The presence of the silicides has been indicated as a possible source of the refinement of alpha (Al) and beta (Si) phases. The precipitations of these phases and of the intermetallic phases favour a high degree of the silumins hardening. A characteristic feature is the fact that nucleation and crystallisation of the successive phases takes place at the phase boundaries formed between the previously precipitated phase and solid solution alpha. The studies carried out so far have indicated that in complex silumins at high temperatures crystallise the silicides and peritectic phases of Al12W, AlWSi, Al12Mo and Al13Cr4Si4. Phases alpha or beta are the next ones to crystallise, followed by complex eutectic alpha + beta +Al(Si, Cr, Mo, W, Fe). Further crystallise the phases of Mg2Si, Al3Ni and Al2Cu. The silumins presented here are characterised by high mechanical properties: Rp0,2=320-420MPa, Rm=400-520MPa, A5=0.5-5.0% and elevated hardness of 145-210HB. Further investigations will be carried out to optimise the chemical composition of silumins and the precipitation hardening process parameters to produce alloys characterised by optimum combination of strength, ductility and hardness.

2

Korelacja pomiędzy ilościowym opisem mikrostruktury, a właściwościami mechanicznymi w stali duplex w obecności wodoru

Sozańska M., Kłyk-Spyra K., Lasota J.

Inżynieria Materiałowa

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2003

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R. XXIV, nr 6

369-372

PL

W pracy dokonano ilościowej oceny mikrostruktury stali duplex 2205 po nawodorowaniu. Ustalono zależności pomiędzy uzyskanymi wynikami, a parametrami wytrzymałościowymi uzyskanymi w wyniku poddania badanej stali klasycznej próbie rozciągania statycznego. Wyznaczono udział procentowy austenitu - 45,6% oraz ferrytu - 54,4% wykorzystując metody metalografii ilościowej i następnie porównując otrzymane wyniki z wartościami otrzymanymi metodą rentgenowskiej analizy fazowej. Stwierdzono również, że wartość oszacowanej granicy plastyczności delta 0,2 z wyników otrzymanych metodami metalografii ilościowej jest porównywalna z wartością granicy plastyczności wyznaczonej z badań mechanicznych.

EN

In work was executed a quantitative analysis of microstructure of duplex steel 2205 after hydrogen charged. Dependency among obtained results, and mechanical properties obtained in result of surrendering investigated of steel tensile strength test, was fixed. Proportional participation austenite -45,6% and of ferrite - 54,4% using method of quanitative metallography comparing received results at use of method X-ray analysis's, was marked. One ascertained also, that value of yield strength delta 0,2 received methods of quantitative metallography is comparable with value of yield strength from mechanical researches.

3

Effect processing variables on mechanical properties of sintered manganese steels Fe-3%Mn-0.8%C.

Sułowski M., Ciaś A.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

1179-1182

EN

The powder metallurgy route may allow sintered manganese steels to be made based on pure iron powder and ferromanganese powder with control over alloy microstructure. The factors that contribute to the mechanical properties of sintered Fe-3%Mn-0,8%C manganese steel, such as the sintering atmosphere, dew point, sintering temperature, cooling rate are summarized. The paper shows the influence of these parameters on the tensile strength, yield strength, transverse rupture strength, impact strength and hardness. It showed that tensile high strength level higher then those of many present sintered steels can be obtained already in the as-sintered condition.