THE INTERACTION BETWEEN TOOL MATERIAL, ENVIRONMENT, AND PROCESS CONDITIONS IN THE MACHINING OF ALUMINIUM ALLOYS

1999 ◽  
Vol 3 (2) ◽  
pp. 273-286 ◽  
Author(s):  
W. Y. H. Liew ◽  
I.M. Hutchings ◽  
J. A. Williams
2014 ◽  
Vol 59 (1) ◽  
pp. 385-392
Author(s):  
B. Rams ◽  
A. Pietras ◽  
K. Mroczka

Abstract The article presents application of FSW method for joining elements made of cast aluminium alloys which are hardly weldable with other known welding techniques. Research’s results of plasticizing process of aluminium and moulding of seam weld during different FSW process’ conditions were also presented. Influence of welding parameters, shape and dimensions of tool on weld structure, welding stability and quality was examined. Application of FSW method was exemplified on welding of hemispheres for valves made of cast aluminium alloy EN AC-43200.


Author(s):  
Z. Iqbal ◽  
A. N. Shuaib ◽  
F. Al-Badour ◽  
N. Merah ◽  
A. Bazoune

One of the challenges that impede the use of the relatively new friction stir welding (FSW) process in joining steels and high temperature alloys, as well as dissimilar materials, is the development of the right pin tool material that can stand the severe welding conditions of these alloys. Recent developments in FSW tool materials include tungsten rhenium (W-Re) alloys. The ductile to brittle transition temperature of pure tungsten is reduced by the addition of rhenium (Re).. The addition of Re also improve fracture toughness of the alloy. The major focus of this paper is studying the process of making a friction stir welding bead on mild steel using a proprietary W-25%Re alloy pin tool and investigating the effects of process parameters (i.e. tool rotational and welding speeds) on microstructure, microhardness as well as tool reaction loads. Grain refining of the steel microstructure was observed in all beads. Certain process conditions produced a bead with needle like microstructure with the highest values of hardness. Reaction forces were found to increase with the increase in the tool welding speed and to decrease with the increase of the tool rotational speed. Although the spectroscopic analysis of the beads confirmed the diffusion wear of the tool, the overall tool has shown excellent resistance to mechanical wear.


2010 ◽  
Vol 107 ◽  
pp. 117-121 ◽  
Author(s):  
Rafael Bienvenido ◽  
J.E. Díaz Vázquez ◽  
Francisco Javier Botana ◽  
M.J. Cano ◽  
Mariano Marcos Bárcena

In the aeronautical industrial sector, the control of the manufacturing process allows to fit the results to the conditions of design of pieces. This manufacturing process conditions the functional behaviour of pieces. In this work are presented the preliminary results of a study conducing to obtain the influence of machining parameters in the response to corrosion of aerospace aluminium alloys in seawater. This results show a high influence of feed, and a minor influence of cutting speed.


2012 ◽  
Vol 710 ◽  
pp. 43-49
Author(s):  
Laurens Katgerman ◽  
Dmitry G. Eskin

Research activities on aluminium production technology focus on the successive steps in the production chain of aluminium wrought products. Direct-chill casting of aluminium alloys is a well-developed technology with a long history. But only in the last 20 years, the development of computer modelling offered a means of better understanding of the physical phenomena involved in solidification. The main scientific challenge is to obtain a fundamental insight into the processing of aluminium alloys and to establish quantitative relationships between materials, processes, and performance. A systems approach is employed, covering theoretical and experimental studies on processing into semi-finished products. Special emphasis is placed on experimental verification and industrial applicability with the availability of pilot scale experimental facilities at M2i-TUD. This facilitates the design of process conditions as desired for experimental validation studies. In this paper we will consider main mechanisms of structure and defect formation during solidification of DC cast billets, mostly based in the results obtained in cooperation between Delft University of Technology and Materials Innovation Institute (M2i).


2018 ◽  
Vol 91 (2) ◽  
pp. 390-400 ◽  
Author(s):  
Barbora Hanulikova ◽  
Dana Shejbalova ◽  
Zdenek Dvorak

ABSTRACT Mold fouling during the crosslinking process of EPDM rubber compounds results in defects in compression-molded products and deterioration of process conditions. Moreover, subsequent cleaning of molds is expensive and causes a loss at production. The fouling of several types of steel and aluminum alloys, which represent molds with variously machined surfaces, was analyzed during 0–70 cycles of EPDM molding. Fourier transform infrared microscopy was used for investigation of fouling and paraffin oil (softener) and/or EPDM fragments were detected in vibrational spectra of fouling as the most probable components of it. Metal specimens with a grinded surface were found to be more resistant to EPDM residue deposition.


2015 ◽  
Vol 41 (1) ◽  
pp. 25-40 ◽  
Author(s):  
Chris Baber

Abstract In this paper, I question the notion that tool-use must be driven by an internal representation which specifies the “motor program” enacted in the behaviour of the tool-user. Rather, it makes more sense to define tool-use in terms of characteristics of the dynamics of this behaviour. As the behaviour needs to be adjusted to suit changes in context, so there is unlikely to be a one-to-one, linear mapping between an action and its effect. Thus, tool-use can best be described using concepts from Nonlinear Dynamics. Such an approach can be used to create a sort of cybernetic model of tool-use. However, there is a danger that such a model can either lead us back to internal representations (in that the comparator used to evaluate feedback during behaviour could be assumed to be pre-defined) or could fail to capture cognitive aspects of behaviour. In particular, the question of how the craftworker’s intent can be enacted in the use of tools to produce a specific object seems to be lost in the cybernetic account. My solution is two-fold. First, the “model” is created on-the-fly and adapted through moment-by-moment interactions in the system of tool-user–tool–material–environment. This means that, rather than assuming a pre-defined internal representation that drives behaviour, I propose that cognition involves the selection of salient parameters that characterize the behaviour and the continued monitoring and management of behaviour in terms of these parameters. Second, intent is only loosely defined a priori but crystallizes through the continued interactions between craftworker and object through a process in which the affordances of the object become apparent to, and responded to by, the craftworker.


Author(s):  
J. Temple Black

The output of the ultramicrotomy process with its high strain levels is dependent upon the input, ie., the nature of the material being machined. Apart from the geometrical constraints offered by the rake and clearance faces of the tool, each material is free to deform in whatever manner necessary to satisfy its material structure and interatomic constraints. Noncrystalline materials appear to survive the process undamaged when observed in the TEM. As has been demonstrated however microtomed plastics do in fact suffer damage to the top and bottom surfaces of the section regardless of the sharpness of the cutting edge or the tool material. The energy required to seperate the section from the block is not easily propogated through the section because the material is amorphous in nature and has no preferred crystalline planes upon which defects can move large distances to relieve the applied stress. Thus, the cutting stresses are supported elastically in the internal or bulk and plastically in the surfaces. The elastic strain can be recovered while the plastic strain is not reversible and will remain in the section after cutting is complete.


Author(s):  
V. C. Kannan ◽  
A. K. Singh ◽  
R. B. Irwin ◽  
S. Chittipeddi ◽  
F. D. Nkansah ◽  
...  

Titanium nitride (TiN) films have historically been used as diffusion barrier between silicon and aluminum, as an adhesion layer for tungsten deposition and as an interconnect material etc. Recently, the role of TiN films as contact barriers in very large scale silicon integrated circuits (VLSI) has been extensively studied. TiN films have resistivities on the order of 20μ Ω-cm which is much lower than that of titanium (nearly 66μ Ω-cm). Deposited TiN films show resistivities which vary from 20 to 100μ Ω-cm depending upon the type of deposition and process conditions. TiNx is known to have a NaCl type crystal structure for a wide range of compositions. Change in color from metallic luster to gold reflects the stabilization of the TiNx (FCC) phase over the close packed Ti(N) hexagonal phase. It was found that TiN (1:1) ideal composition with the FCC (NaCl-type) structure gives the best electrical property.


Author(s):  
A. Cziráki ◽  
E. Ková-csetényi ◽  
T. Torma ◽  
T. Turmezey

It is known that the formation of cavities during superplastic deformation can be correlated with the development of stress concentrations at irregularities along grain boundaries such as particles, ledges and triple points. In commercial aluminium alloys Al-Fe-Si particles or other coarse constituents may play an important role in cavity formation.Cavity formation during superplastic deformation was studied by optical metallography and transmission scanning electron microscopic investigations on Al-Mg-Si and Al-Mg-Mn alloys. The structure of particles was characterized by selected area diffraction and X-ray micro analysis. The volume fraction of “voids” was determined on mechanically polished surface.It was found by electron microscopy that strongly deformed regions are formed during superplastic forming at grain boundaries and around coarse particles.According to electron diffraction measurements these areas consist of small micro crystallized regions. See Fig.l.Comparing the volume fraction and morphology of cavities found by optical microscopy a good correlation was established between that of micro crystalline regions.


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