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Research on the properties of Co-TiC and Ni-TiC HiP-sintered alloys

Cherepova Tetiana, Dmitrieva Galyna, Tisov Oleksandr, Dukhota Oleksandr, Kindrachuk Myroslav

Acta Mechanica et Automatica

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2019

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Vol. 13, no. 1

57--67

EN

Three types of sintered alloys were fabricated based on cobalt, nickel and high-temperature alloy ZhS32-VI matrix with titanium carbide strengthening phase. TiC content was in a range of 30–50 vol. %. The melting temperatures of alloys are higher than 1320°C, and they may undergo undamaged through all technological procedures together with turbine blades, including soldering and outgassing. DSC analyses indicates no additional thermal effects until melting, which confirms their structural stability. The examinations of microstructure revealed three types of constituents – TiC particles, matrix solid solution and blow outs – structural defects having negative effects on all the studied properties. It was found that heat resistance of nickel based sintered alloys at the temperature of 1100°C is superior as compared with the alloys based on cobalt and alloy ZhS32-VI. It has been established that wear resistance in conditions of fretting wear at temperatures of 20, 850, 950 and 1050°C of sintered alloy with ZhS32-VI matrix is mostly superior as compared with the other alloys. The properties of produced alloys allow to use them for manufacturing of components of friction couples operating in conditions of high temperature fretting wear, including protective pads of turbine blades top shrouds contact faces.

2

Structural characterization of sintered DistaloyAE and DistaloyHP

Skrzypek S. J., Bergmark A., Goły M.

Inżynieria Materiałowa

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2013

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Vol. 34, nr 4

370--373

EN

The purpose of this paper is to elaborate X-ray diffraction methodology to characterize some chosen qualitative parameters of diffusion alloyed PM steel DistaloyAE and DistaloyHP. The beneﬁcial feature of diffraction methods is the non-destructive character and large number of structural information contained in diffraction pattern. X-ray diffraction have large potential in analysis of technological operations and fatigue or corrosion life. Qualitative and quantitative phase analysis and residual stresses (01) obtained by the classical sin2 Ψ and modiﬁed g-sin2 Ψ are presented. The proﬁle diffraction line analysis was used to determine lattice distortion and average crystallite size (D). In H6 and H8 samples distortions are higher than in A5 and A8. The decreases versus depth and largest values appear in about 4 um thick surface layer of A samples and in about 4÷10 um thick surface layer of H one. In all samples occurred tensile stresses. Higher value of stresses was in H samples.

PL

Zastosowano specjalną metodologię rentgenowskich metod dyfrakcyjnych w celu scharakteryzowania warstw wierzchnich spieków wykonanych z dwóch stopów DistaloyAE and DistaloyHP. Drugim celem było potencjalne zastosowanie dyfrakcyjnych metod jako sposobu nieniszczącej kontroli jakości procesu technologii spiekania, a także nieniszczących obserwacji strukturalnych efektów zmęczeniowych i korozyjnych stopowych stali spiekanych. Cele zrealizowano, stosując jakościową i ilościową dyfrakcyjną analizę fazową, dyfrakcyjną metodę pomiaru makroskopowych naprężeń własnych (01) i metodę analizy proﬁlu linii dyfrakcyjnej umożliwiające wyznaczenie mikroodkształceń sieci krystalicznej oraz średniej wielkości ziarna (D). Średnia wielkość ziama w próbkach A5 i A8 jest prawie dwukrotnie Większa niż w próbkach H6 i H8. Mikroodkształcenia sieci krystalicznej są większe w próbkach H6 i H8. We wszystkich próbkach maleje wraz ze wzrostem głębokości. Maksymalne wartości mikroodkształceń występowały dla grubości warstwy ok. 4 um dla próbek A i do 10 um dla próbek H. We wszystkich próbkach występowały naprężenia rozciągające. Większe wartości naprężeń występowały dla próbek H.

3

Modelling of the mechanical behaviour of porous materials: a new approach

Cosmi F., Di Marino F.

Acta of Bioengineering and Biomechanics

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2001

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Vol. 3, nr 2

55-66

EN

A new approach to porous materials modelling is presented. In this model, a matrix of cells contains a number of randomly distributed void cells in order to obtain the desired porosity. The system is solved by means of a recent numerical method, the Cell Method. As an application, the Young modulus of four sintered alloys is computed and the simulations show a good agreement with the experimental results reported in literature, depending on the porosity of the sintered powder and the Young modulus of the wrought material. Besides this application, the approach is promising in a wider class of problems, namely all those in which a large number of random distributed heterogeneities or voids are present.