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Effect of strain rate on the shift of neutral layer in AZ31B alloys during V-bending at warm conditions
Full text linkThe effects of strain rate on the shift of neutral layer in AZ31B magnesium alloy sheets were investigated
by V-bending tests with a strain rate of 10-2 s-1, 10-3 s-1, 10-4 s-1 at 423 K. Besides, tension and
compression tests on AZ31 Mg sheets along the rolling direction (RD) were also conducted at various
strain rates. The results show that the neutral layer of Mg alloys shifts to the outer tensile region during
bending and the shifting offset decreases with the strain rate decreasing. The above result is a direct
consequence of the observed weakening of the tension-compression asymmetry of the Mg alloy at
decreasing strain rate
The effects of detwinning on the mechanical properties of AZ31B magnesium alloy with different strain rates at 423K
Full text linkEffect of twinning and detwinning on the spring-back and shift of neutral layer in AZ31 magnesium alloy sheets during V-bend
Full text linkIn order to investigate the effect of twinning and detwinning on springback and shift of neutral layer,
pre-stretch (PRS) of 3% and 5%, and pre-compression (PRC) of 1%, 3% and 5% along rolling direction
was conducted in an AZ31 magnesium alloy sheets at room temperature. 90 V-bending tests were
performed at 423 K with various pre-strained samples. The results show that springback increases after
both PRS and PRC deformation. The coefficient of neutral layer (k-value) decreases with the increase of
the levels of PRS and PRC. After PRS, twinning in an inner compressive region during bending is restrained
and tension–compression asymmetry decreased. After PRC, detwinning occurs which implying that it
dominates the deformation in the outer tensile region, while in inner compressive region twinning still
governs the deformation. Twinning and detwinning leads to a decrease of asymmetry mechanism
between the outer and inner layers. The decrease of asymmetry mechanism after PRT and PRC results
in a drop of the neutral layer offset
The effect of twinning and detwinning on the mechanical property of AZ31 extruded magnesium alloy during strain-path changes
Full text linkIn order to investigate the effect of twinning–detwinning on the mechanical properties of AZ31 extruded
magnesium alloy pre-compression and pre-stretch deformation were conducted along extrusion direction
(ED) at 1%, 3%, 5% strain levels. After pre-strain, the strain-path was inverted by performing tensile
or compressive tests at room temperature. Results showed that the detwinning behavior occurred during
the inverse tension after the pre-compression. Although due to the aforementioned effect the tensile
yield strength decreased, by increasing the pre-compressive levels both fracture elongation and peak
strength improved. In the inverse compressive tests after pre-stretch the {1012} twinning was
restrained and the volume fraction of twins decreased, leading to the improvement of yield strength
by increasing in pre-stretching levels
Formability and anisotropy of the mechanical properties in commercially pure titanium after various routes normal and different speed rolling
No full textVarious routes (unidirectional, cross, and three directions) normal and different speed rolling (DSR) are conducted on pure titanium sheet at 673 K and sequent 933 K annealing is followed. The results show that transverse direction (TD)-split double peak texture is kept during unidirectional rolling and a fiber basal texture is formed after cross and three-direction rolling. However, TD-split texture is preserved and rotates about 45° while the fiber basal texture is generated after cross and three direction rolling combining (DSTDR) DSR, respectively. This may
be related to the changed strain path and induced shear deformation as well as thermal activation. Due to rotation of grains, the anisotropy of mechanical properties of Ti sheets decreases, especially in various DSR routes. Erichsen value is improved greatly in DSTDR specimens
Effects of texture and grain size on mechanical properties of AZ80 magnesium alloys at lower temperatures
Full text linkIn order to investigate the effect of texture and grain size on mechanical properties of AZ80 magnesium alloy at lower temperatures, ECAP was conducted for 1, 2 and 4 passes at 523 K. Tensile and compressive tests were carried out on the ECAP processed samples at roomtemperature, 373 K and 423 K, respectively. The results showed that a significant grain refinement took place and the original extrusion fiber texture evolved into a new preferred crystal orientation, featuring a favorable alignment of the basal planes along shear planes after ECAP process.
At room temperature grain refinement strengthening played an important role, leading to an improvement of mechanical properties with increasing number of ECAP passes. However, at higher temperature, texture and grain boundary sliding (GBS) mechanisms controlling deformation behaviors, resulting in a softening effect and considerable fracture elongation improvement, as well as yield asymmetry reduction
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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