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Subsurface deformation and burr formation in nickel-based single-crystal superalloy under grinding

Liang Chunyou, Gong Yadong, Li Pengfei, Sun Jingyu, Jin Liya, Yin Guoqiang, Wen Xuelong, Bo Xin

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e126, 2023

EN

Machined subsurface and burr of nickel-based single-crystal superalloys (SXs) were identified as a key factor to the aero-engine industrial requirements concerning high service performance and the precision of edge geometry, in particular the finishing operations as grinding. To clarify subsurface deformation behaviors and the mechanisms of burr formation when grinding SXs, first, the present investigation predicted slip stresses acting on slip systems in workpiece subsurface under grinding based on the theory of resolved shear stress in single crystal, and correlated theoretical possible slip traces with experimental observed slip band systems. Second, grinding experiments on nickel-based SXs with [00-1]/[010], [11-3]/[332], [-110]/[111] and [-1-1-1]/[-110] orientations were performed to determine the anisotropy deformational behaviors of workpiece subsurface. Lastly, the unreported free surface of burr was adopted to investigate the formation mechanisms for side burrs and exit burrs during grinding. Results show that subsurface deformation patterns present anisotropy and resolved shear stress contribute to slip in nickel-based SXs. High shear density layers/zones consisting of interacted slip bands are found in grinding-induced sub-surfaces. Slip induced plasticity is the dominant deformation mechanism in the formation process of side burrs and exit burrs in grinding of nickel-based SXs.

2

Mechanisms of plastic deformation in light high-manganese steel of TRIPLEX type

Sozańska-Jędrasik Liwia, Borek Wojciech, Mazurkiewicz Janusz

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 5

art. no. e137412

EN

In this scientific publication, research results of two newly developed hot-rolled Fe-Mn-Al-C (X105) and Fe-Mn-Al-Nb-Ti-C (X98) types of steel were compared. These types of steel are characterized by an average density of 6.68 g/cm³, a value 15% lower compared to conventional structural steel. Hot rolling was carried out on a semi-industrial line to evaluate the effect of hot plastic deformation conditions with different cooling variants on the structure. The detailed analysis of phase composition as well as microstructure allows us to state that the investigated steel is characterized by an austenitic-ferritic structure with carbides precipitates. The results of the transmission electron microscopy (TEM) tests of both types of steel after hot rolling showed the occurrence of various deformation effects such as shear bands, micro bands, and lens twins in the microstructure. Based on the research undertaken with the use of transmission electron microscopy, it was found that the hardening mechanism of the X98 and X105 steel is deformation-induced plasticity by the formation of shear bands (SIP) and micro shear bands (MBIP).

3

Modelowanie rozwoju odkształcenia zachodzącego przez poślizg na oddzielnych powierzchniach w ciele dwuwymiarowym z zastosowaniem metody elementów skończonych

Kukliński M.

Logistyka

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2014

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nr 6

6329-6336

PL

Podczas opisu procesu odkształcenia w skali rzędu odległości międzyatomowych nie można założyć jednorodności struktury metalu, gdyż materiały tego typu odkształcają się plastycznie przez poślizg na oddzielnych powierzchniach, które są miejscami nieciągłości funkcji odkształceń. Pojawia się więc konieczność zrozumienia procesu aktywacji powierzchni poślizgu i powstawania pasm poślizgu w celu wypracowania numerycznych metod modelowania tych zjawisk. Próby symulacji procesu aktywowania powierzchni poślizgu w modelu jednowymiarowym zostały już przeprowadzone wcześniej. Przeanalizowano kinematykę i termodynamikę procesu aktywacji powierzchni poślizgu. W niniejszej pracy przedstawiono metodę modelowania odkształcenia ciała dwuwymiarowego ulegającego poślizgom na oddzielnych powierzchniach. Rozszerzenie zagadnienia wyłoniło nowe jakościowe problemy. W modelu dwuwymiarowym powierzchnia poślizgu pojawia się początkowo w punkcie, a następnie ewoluuje aż do całkowitego przecięcia przyjętego modelu. Ta sytuacja została opisana i numerycznie zasymulowana. Następnym zagadnieniem, które pojawiło się podczas modelowania dwuwymiarowego jest transfer wielkości pomiędzy poruszającymi się na powierzchni węzłami. Przyjęto liniową aproksymację wartości zmiennych pomiędzy węzłami. To przybliżenie może być polepszone w następnej pracy.

EN

Describing the evolution of deformation in scale comparable with interatomic distances one is not allowed to assume homogenous structure of metals, since these types of material undergo slips on separated surfaces, which constitute discontinuities of deformation function. Surges necessity of profound understanding of processes of slip activation and formation of slip bands in order to work out numerical methods of modelling this type of phenomena. Attempts to model the processes of slip activation in one-dimensional body had been carried out earlier. Kinematics and thermodynamics of this process had also been analysed. This paper presents the modelling method of deformation of two-dimensional body undergoing slips on separate surfaces. As a result of such an extension a new qualitative problems appeared and have been discussed. In two-dimensional model a slip surface initially surges in a point, and then evolve until total section of modelled body. The next issue is the transfer of quantities between nods moving on a slip surface. Also equations of finite element method for two-dimensional body have been derived, balance of energy for the case with slip surface has been carried out and numerical simulations have been realized. A linear approximation of variables between nods was assumed and this approach can be improved.

4

Plastic strain in metals by shear banding. [Pt.] 1, Constitutive description for simulation of metal shaping operations

Pęcherski R. B., Korbel K.

Archives of Mechanics

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2002

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Vol. 54, nr 5-6

603-620

EN

The aim of the paper is to study the description of plastic strain in metals produced by a hierarchy of plastic slip and shear banding processes: from slip lamellae and slip bands to coarse slip bands, which may further transform into transgranular micro-shear bands and form clusters of micro-shear bands. Constitutive description accounting for the contribution of shear banding was proposed and possible simplifications are discussed from the point of view of applications for numerical simulation of metal shaping operations.