Characterization of material strain and thermal softening effects in the cutting process

Author(s):  
Dong Zhang ◽  
Xiao-Ming Zhang ◽  
Guang-Chao Nie ◽  
Zheng-Yan Yang ◽  
Han Ding
2010 ◽  
pp. 70-79
Author(s):  
Sergio Saponara ◽  
Fabrizio Iacopetti ◽  
Luca Fanucci ◽  
Bruno Neri

The paper presents an experimental characterization of wireless systems, specifically RFID technologies, applied to polishing/cutting process control in the marble industry. The application of RFID systems has the final aim of allowing the automatic and contact-less detection of the presence of a marble slab in different points of a marble machine, outside and/or inside, trying to overcome some limitations of the currently used proximity detectors. Slab detection is needed for the process control in order to properly activate the abrasive or cutting heads of the machine. Four RFID systems at 125 kHz, 13.56 MHz, 868 MHz and 2.45 GHz have been tested in different set-ups representative of those found in marble machines. Starting from commercially available tags, readers and antennas, ad-hoc developed or customized hardware and/or software have been used for the experimental test campaign, that has been carried out also considering dirty and wet working environments representative of those found in real applications.


1999 ◽  
Vol 591 ◽  
Author(s):  
A. Rabiei ◽  
J. W. Hutchinson ◽  
A. G. Evans

ABSTRACTHeat generation from a notch during the compression-compression fatigue of a cellular Al alloy has been measured and compared with a model. The measurements indicate that heat is generated because of hysteresis occurring in narrow cyclic plastic zones outside the notch. This process continues until the notch closes. At closure, a brief period of heat generation arises because of friction along the notch faces. A plasticity model based on the Dugdale zone is shown to provide a reasonably accurate characterization of the heat generated, with the proviso that an “ineffective” zone be transposed onto the notch tip. It is found that the temperatures generated are too small to cause fatigue by thermal softening. A fatigue mechanism based on either geometric softening of the cells or crack growth in the cell walls is implied.


2016 ◽  
Vol 725 ◽  
pp. 138-142
Author(s):  
Ming Jun Piao ◽  
Hoon Huh ◽  
Ik Jin Lee

This paper is concerned with the characterization of the OFHC copper flow stress at strain rates ranging from 10−3 s−1 to 106 s−1 considering the large strain and high temperature effects. Several uniaxial material tests with OFHC copper are performed at a wide range of strain rates from 10−3 s−1 to 103 s−1 by using a INSTRON 5583, a High Speed Material Testing Machine (HSMTM), and a tension split Hopkinson pressure bar. In order to consider the thermal softening effect, tensile tests at 25°C and 200°C are performed at strain rates of 10−3 s−1,101 s−1, and 102 s−1. A modified thermal softening model is considered for the accurate application of the thermal softening effect at high strain rates. The large strain behavior is challenged by using the swift power law model. The high strain rates behavior is fitted with the Lim–Huh model. The hardening curves are evaluated by comparing the final shape of the projectile from numerical simulation results with the Taylor impact tests.


Author(s):  
B. L. Soloff ◽  
T. A. Rado

Mycobacteriophage R1 was originally isolated from a lysogenic culture of M. butyricum. The virus was propagated on a leucine-requiring derivative of M. smegmatis, 607 leu−, isolated by nitrosoguanidine mutagenesis of typestrain ATCC 607. Growth was accomplished in a minimal medium containing glycerol and glucose as carbon source and enriched by the addition of 80 μg/ ml L-leucine. Bacteria in early logarithmic growth phase were infected with virus at a multiplicity of 5, and incubated with aeration for 8 hours. The partially lysed suspension was diluted 1:10 in growth medium and incubated for a further 8 hours. This permitted stationary phase cells to re-enter logarithmic growth and resulted in complete lysis of the culture.


Author(s):  
A.R. Pelton ◽  
A.F. Marshall ◽  
Y.S. Lee

Amorphous materials are of current interest due to their desirable mechanical, electrical and magnetic properties. Furthermore, crystallizing amorphous alloys provides an avenue for discerning sequential and competitive phases thus allowing access to otherwise inaccessible crystalline structures. Previous studies have shown the benefits of using AEM to determine crystal structures and compositions of partially crystallized alloys. The present paper will discuss the AEM characterization of crystallized Cu-Ti and Ni-Ti amorphous films.Cu60Ti40: The amorphous alloy Cu60Ti40, when continuously heated, forms a simple intermediate, macrocrystalline phase which then transforms to the ordered, equilibrium Cu3Ti2 phase. However, contrary to what one would expect from kinetic considerations, isothermal annealing below the isochronal crystallization temperature results in direct nucleation and growth of Cu3Ti2 from the amorphous matrix.


Author(s):  
B. H. Kear ◽  
J. M. Oblak

A nickel-base superalloy is essentially a Ni/Cr solid solution hardened by additions of Al (Ti, Nb, etc.) to precipitate a coherent, ordered phase. In most commercial alloy systems, e.g. B-1900, IN-100 and Mar-M200, the stable precipitate is Ni3 (Al,Ti) γ′, with an LI2structure. In A lloy 901 the normal precipitate is metastable Nis Ti3 γ′ ; the stable phase is a hexagonal Do2 4 structure. In Alloy 718 the strengthening precipitate is metastable γ″, which has a body-centered tetragonal D022 structure.Precipitate MorphologyIn most systems the ordered γ′ phase forms by a continuous precipitation re-action, which gives rise to a uniform intragranular dispersion of precipitate particles. For zero γ/γ′ misfit, the γ′ precipitates assume a spheroidal.


Author(s):  
R. E. Herfert

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.


Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.


Author(s):  
Simon Thomas

Trends in the technology development of very large scale integrated circuits (VLSI) have been in the direction of higher density of components with smaller dimensions. The scaling down of device dimensions has been not only laterally but also in depth. Such efforts in miniaturization bring with them new developments in materials and processing. Successful implementation of these efforts is, to a large extent, dependent on the proper understanding of the material properties, process technologies and reliability issues, through adequate analytical studies. The analytical instrumentation technology has, fortunately, kept pace with the basic requirements of devices with lateral dimensions in the micron/ submicron range and depths of the order of nonometers. Often, newer analytical techniques have emerged or the more conventional techniques have been adapted to meet the more stringent requirements. As such, a variety of analytical techniques are available today to aid an analyst in the efforts of VLSI process evaluation. Generally such analytical efforts are divided into the characterization of materials, evaluation of processing steps and the analysis of failures.


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