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1

Effect of material microstructure on tool wear behavior during machining additively manufactured Ti6Al4V

Dang Jiaqiang, Cai Xiaojiang, Yu Dedong, An Qinglong, Ming Weiwei, Chen Ming

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 1

41--55

EN

Additive Manufacturing (AM) technologies are increasingly applied in various industries since they provide the possibility to manufacture the components with high geometrical complexity easier and faster than traditional processes. However, the subsequent semi-finish/finish machining operations such as drilling, turning and/or milling are still necessary for AM parts to obtain the required surface textures and meet the practical requirements. As such, the AM parts usually indicate different machinability compared with conventionally produced ones in view of the different material microstructures. A comprehensive understanding of this machining effort is of great importance for similar engineering applications but not widely reported. Thus, an attempt was made in this work to address the effect of the material microstructure on the machining stability and tool wear behavior in dry drilling of the hard titanium alloys. The experimental results highlight a correlation between the tool wear behavior and material microstructures. A great number of micro-pits appeared on the tool flank face and the abrasive marks, coating delamination, as well as catastrophic failure of the cutting edge were found to be more obvious during machining the DMLS alloy. In contrast, adhesion wear followed by micro chipping and build-up edge were distinguished when machining the wrought Ti6Al4V. Meanwhile, heat treatment can improve the flow plasticity and reduce the brittleness of the AM material since catastrophic failure disappeared and chip adhesion becomes more predominant when machining the HTDMLS Ti6Al4V.

2

Effect of selected Friction Stir Welding parameters on mechanical properties of joints

Kossakowski P. G., Wciślik W., Bakalarz M.

Archives of Civil Engineering

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2019

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Vol. 65, nr 4

51--62

EN

The article discusses the basic issues related to the technology of friction stir welding (FSW). A short description of technology is provided. The following section provides the analysis of effect of technological parameters (tool rotation and welding speed) on the mechanical properties of the prepared joint (strength, ductility, microhardness). In both cases the analysis refers to aluminum alloys (6056 and AA2195-T0). The comparative analysis showed the phenomenon of the increase in weld strength along with the increase in the rotational speed of the tool during welding. Similarly, with the increase in welding speed, an increase in weld strength was observed. Some exceptions have been observed from the above relations, as described in the article. In addition, examples of material hardness distribution in the joint are presented, indicating their lack of symmetry, caused by the rotational movement of the tool. The analyses were performed basing on the literature data.

PL

W artykule przedstawiono podstawowe zagadnienia związane z wpływem wybranych parametrów technologii zgrzewania tarciowego (prędkość obrotowa i liniowa narzędzia) na właściwości mechaniczne gotowej spoiny, ze szczególnym uwzględnieniem zależności naprężenie-odkształcenie i twardości materiału.

3

Analysis of the heterogeneous weld joints in aspect of fracture mechanics

Ratanowski E.

Journal of Polish CIMAC

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2011

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Vol. 6, no 3

245-252

EN

This paper will discuss the issues relating to the effect of constraint on the fracture safe design. At first the attention is focused on the relation between the microstructure and selected mechanical properties. This aspect is illustrated with presenting a brief consideration of the constraint effect in relation: microstructure - mechanical properties in microscopic scale. The same problem is account in macroscopic scale of the heterogeneous weld joints. After formulating a simplified model of mismatched weld joints a concise review of stress was made at interfaces between zones (W) and (B). Conclusions from above analysis form a constraint parameters un / ov R K which were used to an assessment of the fracture parameters as ratio of driving forces un / ov R d by modified of the classical solution presented by Engineering Treatment Model (E-T-M).

4

Edge Detection and Filtering Approach Dedicated to Microstructure Images Analysis

Rauch Ł., Kusiak J.

Computer Methods in Materials Science

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2007

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Vol. 7, No. 2

305-310

EN

The automated analysis of images plays important role in very wide range of applications. One of such fields of interest is processing of microstructure images used to determine material grains, perform statistical calculations or prepare material model for FEM simulations. However, in all mentioned previously applications the preprocessing stage, which includes edges detection in material structure, has to be completed. The microstructure images, in most cases, consist of a set of various shapes with different sizes, what affects final efficiency and reliability of the results obtained after images preprocessing. Moreover, most of the images possess superimposed noise in form of dark spots originating from various chemical elements inside analyzed material. Unfortunately, the most of currently applied algorithms dedicated for edges detection or image segmentation e.g. Canny Detector do not cope with these problems, returning unsatisfactory results. The tests performed with application of smoothing algorithms did not success as well. In this paper authors presents the solution based on the combination of two different approaches - Particle Dynamic method dedicated for automated denoising of input images and Modified Canny Detector algorithm for edges processing. The first phase of the proposed method aims to remove additional noise from microstructure images. This functionality is performed in automated manner by minimizing set of parameters, which have to be setup before data processing. Due to this solution the time cost of data analysis is highly reduced, relieving researcher from performing many manual activities. The objective of the Modified Canny Detector algorithm is to process the image to obtain edges in the following steps: convolution filtering, edge suppression, small groups of pixels elimination. Additionally the Watershed algorithm was implemented to fulfill the edges of grains. The results obtained by application of proposed approach in comparison to other conventional methods are presented as well.

PL

Przetwarzanie obrazów mikrostruktur w celu detekcji granic między ziarnami jest wciąż trudnym zadaniem. Spowodowane jest to przede wszystkim występującym na zdjęciach szumem w postaci zarysowań lub mikro wtrąceń. Dlatego też w większości przypadków analiza zdjęć nadal wykonywana jest ręcznie, co dla dużego zbioru obrazów jest bardzo czasochłonne. Aby uniknąć tego problemu, zaproponowano podejście automatycznego przetwarzania obrazów składającego się z dwóch części tj. wykrywanie krawędzi, zaprojektowane i zaimplementowane na podstawie algorytmu Canny Detector (Ritter & Wilson, 1996) oraz filtrowania danych w oparciu o metodę cząstek dynamicznych (Rauch & Kusiak, 2005a). W wyniku zastosowania tego podejścia powstaje nowy obraz mikrostruktury z wygładzonymi obszarami ziaren oraz precyzyjnie zdefiniowanymi granicami. Osiągnięty efekt umożliwia optymalizację procesu dalszej analizy struktury materiału np.: przy użyciu algorytmu uzupełniania granic Watershed (Haris et al., 1998) czy też obliczeń statystycznych średniego rozmiaru ziaren. Artykuł przedstawia podstawowe założenia proponowanego podejścia oraz szczegóły implementacji obydwu algorytmów składowych. Wyniki przeprowadzonej analizy obrazów mikrostruktur zostały również przedstawione w niniejszym artykule.