Journal Information
Vol. 8. Issue 3.
Pages 3167-3174 (May - June 2019)
Share
Share
Download PDF
More article options
Visits
318
Vol. 8. Issue 3.
Pages 3167-3174 (May - June 2019)
Original Article
DOI: 10.1016/j.jmrt.2018.11.020
Open Access
Microstructural characteristics of magnesium alloy sheets subjected to high-speed rolling and their rolling temperature dependence
Visits
318
Jeong Hun Leea, Sang Won Leeb, Sung Hyuk Parkb,
Corresponding author
sh.park@knu.ac.kr

Corresponding author.
a Advanced Forming Process R&D Group, Korea Institute of Industrial Technology, Ulsan 44413, Republic of Korea
b School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea
This item has received
318
Visits

Under a Creative Commons license
Article information
Abstract
Full Text
Bibliography
Download PDF
Statistics
Figures (7)
Show moreShow less
Tables (1)
Table 1. Microstructural characteristics of high-speed-rolled samples at different rolling temperatures.
Abstract

Microstructural and textural variations of an AZ31 Mg alloy during its high-speed rolling (HSR) and their dependence on the rolling temperature are investigated by performing HSR at temperatures of 300°C, 350°C, and 400°C at a rolling speed of 470m/min with 80% reduction in a single pass. Shear band formation is observed in all the high-speed-rolled (HSRed) materials; however, with increasing rolling temperature, the density and intensity of the shear bands decrease considerably because of an increase in deformation homogeneity. With increasing rolling temperature, the area fraction of dynamically recrystallized (DRXed) grains gradually increases owing to the promoted twinning-induced recrystallization behavior. With an increase in the rolling temperature from 300°C to 350°C, the average grain size of the HSRed materials decreases owing to the reduced area fraction of coarse unDRXed grains; however, at 400°C, the average grain size increases owing to the increased DRXed grain size. With decreasing rolling temperature, the basal texture of the HSRed materials tilts from the normal direction toward the rolling direction, owing to the intensive shear deformation at lower temperatures. The texture intensity also increases with decreasing rolling temperature because of an increase in the area fraction of the unDRXed region, which has a considerably strong texture.

Keywords:
Magnesium alloy
High-speed rolling
Deformation homogeneity
Dynamic recrystallization
Texture
Full Text
1Introduction

Mg alloys have recently attracted considerable attention in the transportation industry because they have lower densities and higher specific strengths than competitive metal materials such as Al alloys and steels. Mg alloys have been mainly used as casting materials for automobile components such as instrument panels and steering wheels. However, with the development of new process technologies with high productivity and simplified procedures for the fabrication of Mg plates, such as twin-roll casting (TRC) and horizontal continuous casting (HCC), the application range of rolled Mg sheets—which have much better mechanical properties than cast Mg alloys—is expanding rapidly. Even though Mg plates are manufactured by the TRC or HCC process, their limited rollability of 10–30% in a single pass of hot rolling necessitates that they be subjected to several passes and intermediate annealing treatments between the passes to ensure formation of thin Mg sheets for use as automobile components [1,2]. This multipass hot rolling accompanied by heat treatment is a time- and energy-consuming process, and it therefore increases the cost of the final products.

Recently, it has been reported that rolling reduction that can be applied to Mg alloys in a single pass without fracture increases substantially when the rolling is performed at high speeds of >200m/min [3–5]. Su et al. [4] demonstrated that when an AZ31 alloy sheet was rolled at a rolling temperature of 100°C at a conventional low rolling speed of 15m/min, the sheet fragmented into several pieces at a rolling reduction of 37%. However, when the rolling speed was increased to 1000m/min, the sheet could be rolled to a large reduction of 72% in a single pass without fracture. This outstanding rollability that is achievable through high-speed rolling (HSR) is known to be attributed mainly to the promotion of activation of twinning and dynamic recrystallization (DRX) [6], suppression of the formation of macroscopic shear bands [7], and generation of homogeneous deformation throughout the material [8]. Moreover, it has been reported that the activation of additional 〈c+a〉 slip systems during HSR can contribute to an improvement in the rollability of Mg alloys [5,9]. Many studies have been conducted to investigate the mechanisms of DRX occurring during the HSR of cast and wrought Mg alloys, and it has been reported that twinning-induced DRX (TDRX) plays a crucial role in accommodating large plastic deformations and in varying the microstructure of the material [10,11].

Since strain, strain rate, and temperature are the main process parameters under hot deformation conditions, the rolling temperature in the HSR process is expected to have a significant influence on the DRX behavior during rolling and on the resultant microstructure of the material after rolling. Many studies have been conducted to investigate the microstructural and textural evolutions of high-speed-rolled (HSRed) Mg alloys caused by variations in the rolling reduction and rolling speed, which correspond to the process parameters of strain and strain rate, respectively [4,10,11]. However, in-depth research on the effects of the rolling temperature in the HSR of Mg alloys on their microstructural variations has been rarely conducted [3]. In the present study, therefore, the influence of rolling temperature on the microstructural characteristics of HSRed Mg sheets is investigated by performing rolling to a high reduction of 80% at a high speed of 470m/min at different temperatures: 300°C, 350°C, and 400°C. Variations in the deformation homogeneity, grain structure, DRX fraction, and texture of the HSRed materials with the rolling temperature are systematically analyzed.

2Methods

The initial material for this study was a hot-rolled Mg-3.6Al-1.0Zn-0.3Mn (wt%) (AZ31) alloy. The alloy was subjected to homogenization treatment at 400°C for 24h. Subsequently, three samples for rolling were machined from the homogenized alloy; the samples had dimensions of 60mm×50mm×10mm (length×width×thickness), which correspond to the rolling direction (RD), transverse direction (TD), and normal direction (ND), respectively. Each sample was preheated to 300°C, 350°C, and 400°C for 10min prior to rolling and then rolled to a reduction of 80% in just a single pass at a considerably high rolling speed of 470m/min without heating of the rolls. The sheets rolled at 300°C, 350°C, and 400°C are hereafter referred to as HSR300, HSR350, and HSR400 samples, respectively. The average strain and strain rate were calculated using previously reported equations [11]; their calculated values were 1.61 and 181s−1, respectively. The microstructural variations of the HSRed samples with the rolling temperature, i.e., their localized deformation, DRX behavior, grain structure, and crystallographic orientation, were analyzed using optical microscopy (OM), electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) equipment. EBSD measurements were performed at the mid-thickness in the center region of the HSRed samples. The detailed method of EBSD measurements and analysis can be found elsewhere [12].

3Results and discussion3.1Deformation homogeneity during HSR

Fig. 1 shows the optical micrograph and XRD pole figure of the initial material. This material exhibits an equiaxed grain structure with an average grain size of 38.2μm and an intensive basal texture with a maximum texture intensity of 9.1; that is, the basal poles of most grains are oriented nearly parallel to the ND. Fig. 2(a)–(c) shows the optical micrographs obtained on the ND–RD plane of the HSRed samples. Shear bands associated with an abrupt loss of deformation homogeneity are observed in all the HSRed samples; however, the density and intensity of the shear bands decrease with increasing rolling temperature. This result indicates that as the rolling temperature increases, the localized deformation generated during HSR is suppressed and the applied strain is homogeneously imposed over the entire material. When AZ31 alloy samples are hot-rolled at a conventional rolling speed of 14.8m/min, the formed shear bands are inclined at approximately ±30° to the RD [13]. However, in the present study, the shear bands of the HSRed samples are inclined at approximately ±20° to the RD (Fig. 2(a)–(c)); this can be attributed to the intensive shear deformation generated by the high rolling speed of 470m/min. Fig. 2(d)–(f) shows the optical micrographs obtained at the mid-thickness on the TD–RD plane of the HSRed samples. The HSR300 sample exhibits a bimodal grain structure consisting of fine dynamically recrystallized (DRXed) grains and coarse unDRXed grains. In this sample, several deformation twins formed in the unDRXed grains and fine DRXed grains formed at the twins are observed (Fig. 2(d)). Accordingly, the relatively large grains of the initial material (38.2μm) are fragmented by deformation twinning during HSR, and the microstructure is refined by the formation of fine DRXed grains at the twins. The HSR350 sample also contains unDRXed grains, but their size and amount are smaller than those of the unDRXed grains in the HSR300 sample; however, the size of DRXed grains in the HSR350 sample is larger than that of grains in the HSR300 sample (Fig. 2(e)). Therefore, it can be seen that as the rolling temperature increases from 300°C to 350°C, the size difference between the DRXed grains and the unDRXed grains reduces and the microstructural homogeneity increases. The HSR400 sample, in which shear band formation is not noticeable, exhibits an almost fully DRXed grain structure with few unDRXed grains (Fig. 2(f)). However, the DRXed grains in this sample are much larger than those in the HSR300 and HSR350 samples. The microstructural features of the HSRed samples and the differences among these features are identified more clearly through EBSD analysis.

Fig. 1.

(a) Optical micrograph and (b) (0002) X-ray diffraction pole figure of initial material. davg denotes the average grain size.

(0.22MB).
Fig. 2.

Optical micrographs obtained on (a–c) ND–RD and (d–f) TD–RD planes of (a, d) HSR300, (b, e) HSR350, and (c, f) HSR400 samples. ND, RD, and TD denote normal direction, rolling direction, and transverse direction, respectively.

(0.99MB).
3.2Dynamic recrystallization behavior

Inverse pole figure (IPF) maps of the total region and unDRXed region of the HSRed samples are shown in Fig. 3. As the rolling temperature increases from 300°C to 400°C, the area fraction of the unDRXed grains decreases from 25.0% to 1.6%. With each 50°C increase in the rolling temperature, the DRX fraction of the HSRed samples increases by ∼12%. It is known that at high temperatures of ≥300°C, the dominant recrystallization mechanism under hot deformation conditions of Mg alloys is discontinuous DRX (DDRX), which occurs through the nucleation and growth of new strain-free grains [14,15]. The new grains generally nucleate via the local migration of grain boundaries (i.e., grain boundary bulging) [16]. From the viewpoint of the DDRX mechanism, the increase in the DRX fraction of the HSRed samples with increasing rolling temperature is attributable to the promotion of the bulging phenomenon due to the increase in grain boundary mobility. However, under hot deformation conditions with high strain rates, the DDRX behavior is limited even though the deformation temperature is high (≥300°C); this is because of the unavailability of sufficient time for bulging of the grain boundaries. Meanwhile, a twin has a higher effective interface velocity than a slip band; therefore, twinning occurs much more easily than dislocation slip under high-strain-rate deformation; under this condition an insufficient number of slip systems are activated instantaneously [6,17,18]. As a result, it is clear that microstructural evolution during an HSR process with high strain rates is governed by TDRX behavior rather than by DDRX behavior, regardless of the rolling temperature. Fig. 4 shows a partially DRXed grain of the HSR300 sample, in which recrystallization occurs along a twin band formed during HSR. It can be seen that the unDRXed matrix region has a rectangular shape with high aspect ratios of ≥3 owing to the occurrence of recrystallization along the twin band (Fig. 4(b)). It is also observed that fine DRXed grains are formed at grain boundaries in contact with the twin band (region A in Fig. 4(c)). This is because twinning dislocations accumulate at the grain boundary-twin band interface, which increases the driving force for DRX [3,19]. The misorientation line profile along the DRXed grains formed at the twin band reveals that these grains originated from the {10−11} compression twin and the {10−11}–{10−12} double twin (Fig. 4(d)). This finding is consistent with the previously reported result that TDRX dominantly occurs in {10−11} compression twins and {10−11}–{10−12} double twins during the HSR process owing to the high dislocation densities of these twins [11]. As shown in Fig. 2(a)–(c), the distribution of the applied strain over the entire material becomes more uniform as the rolling temperature increases, and this leads to the homogeneous formation of deformation twins and twinning-induced DRXed grains. As a result, the DRX fraction of the HSRed samples increases with an increase in the rolling temperature. In the residual matrix region that is not recrystallized, numerous dislocations continuously accumulate during HSR, leading to significant lattice distortion; it is confirmed that the deviation of the misorientation angle inside a grain is as high as ∼12° (Fig. 4(e)).

Fig. 3.

Inverse pole figure maps of (a, d) HSR300, (b, e) HSR350, and (c, f) HSR400 samples: (a–c) total region and (d–f) unDRXed region. davg and funDRX denote the average grain size and the area fraction of the unDRXed region, respectively.

(1.34MB).
Fig. 4.

Inverse pole figure maps showing twinning-induced DRX behavior in HSR300 sample: (a) total region, (b) unDRXed region, and (c) DRXed region. (d, e) Misorientation line profiles along directions indicated by blue and yellow arrows, respectively, in (a). M, CT, and DT denote the matrix, {10−11} compression twin, and {10−11}–{10−12} double twin, respectively. DRX denotes dynamic recrystallization. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)

(0.65MB).
3.3Variation in grain size of HSRed samples

The average grain size of the HSRed samples decreases from 7.4μm to 6.5μm with an increase in the rolling temperature from 300°C to 350°C, after which it increases to 7.2μm at the rolling temperature of 400°C (Fig. 3). This change is related to the variations in the area fraction of coarse unDRXed grains and the size of relatively fine DRXed grains (Table 1). The average size of the DRXed grains increases with increase in the rolling temperature (Fig. 5(a)–(c)). This is because as the rolling temperature increases, the atomic diffusion at the grain boundaries accelerates, which in turn promotes the growth of newly formed fine DRXed grains. With an increase in the rolling temperature from 300°C to 350°C, the average size of the DRXed grains increases by only ∼16%, from 3.7μm to 4.3μm, and the size distributions of the DRXed grains of the HSR300 and HSR350 samples show a similar tendency (Fig. 5(a), (b), and (d)). On the other hand, an increase in the rolling temperature from 350°C to 400°C causes a large increase of ∼65%—from 4.3μm to 7.1μm—in the average size of the DRXed grains and a considerable widening of the grain size distribution (Fig. 5(b), (c), and (d)). In the HSR300 and HSR350 samples, the plastic deformation applied during HSR is concentrated more or less along the shear bands. In this highly deformed region, a large number of DRXed grains are formed owing to the increased number of nucleation sites for DRX resulting from the high dislocation density. The mutual interference between these DRXed grains in the grain growth stage of the DRX process causes suppression of their further growth, which eventually causes these DRXed grains to have small sizes. The HSR400 sample has an almost fully DRXed grain structure because these grains are formed uniformly over the entire region of the material. However, the density of nucleation sites for DRX in the HSR400 sample is lower than that in the DRXed regions in the HSR300 and HSR350 samples. This lower density facilitates the growth of DRXed grains owing to the reduced mutual interference, which eventually leads to relatively large DRXed grains in the HSR400 sample. Therefore, the average grain size reduction from 7.4μm to 6.5μm with an increase in the rolling temperature from 300°C to 350°C is due to the significant reduction in the area fraction of the coarse unDRXed grains—from 25.0% to 12.5%—even though the DRXed grain size increases from 3.7μm to 4.3μm (Fig. 5(e)). On the other hand, with an increase in the rolling temperature from 350°C to 400°C, the average grain size of the HSRed sample increases from 6.5μm to 7.2μm. With a further increase in the rolling temperature from 350°C to 400°C, the area fraction of the unDRXed grains decreases from 12.5% to 1.6%. However, the size of the DRXed grains—which occupy almost the entire area of the HSR400 sample (98.4%)—increases considerably from 4.3μm to 7.1μm; this consequently results in an increase in the average grain size of the material.

Table 1.

Microstructural characteristics of high-speed-rolled samples at different rolling temperatures.

Rolling temperature (°C)  fDRXa (%)  davgb (μm)  dDRXc (μm)  Imaxd  θmaxe (°) 
300  75.0  7.4  3.7  12.1  37.5 
350  87.5  6.5  4.3  11.2  27.5 
400  98.4  7.2  7.1  7.4  7.5 
a

Area fraction of dynamically recrystallized (DRXed) grains.

b

Average grain sizes of the total region.

c

Average grain sizes of the DRXed region.

d

Maximum intensity of the (0002) pole figure.

e

Deviation angle of basal poles of DRXed grains with the largest area fraction from the normal direction.

Fig. 5.

(a–c) Grain boundary maps and (d) grain size distribution of DRXed region of HSRed samples: (a) HSR300, (b) HSR350, and (c) HSR400. (e) Variations in area fractions and grain sizes of total region and DRXed region with rolling temperature. dDRX denotes the average grain size of the DRXed region. DRX denotes dynamic recrystallization.

(1.41MB).
3.4Textural characteristics of HSRed samples

Fig. 6 shows (0002) pole figures of the unDRXed and DRXed regions and the total region of the HSRed samples. As the rolling temperature increases, the maximum pole intensity decreases from 12.1 to 7.4; this texture weakening is attributed to the reduction in the area fraction of the unDRXed region, which has much higher texture intensities (31.4–48.3) than the DRXed region (7.1–8.4). In addition, in the HSR300 sample, the position with the maximum pole intensity in the DRXed region is considerably deviated from the ND toward the RD; this position gradually approaches the ND as the rolling temperature increases. Fig. 7 shows the variation in the area fraction of the DRXed grains with respect to the deviation angle of the basal poles of the DRXed grains from the ND. The deviation angle corresponding to the maximum area fraction decreases gradually from 37.5° to 7.5° as the rolling temperature increases. Moreover, the distribution range of the deviation angle also reduces with increasing rolling temperature; in the HSR400 sample, the basal poles of ∼92% of the DRXed grains are distributed within 30° from the ND, whereas in the HSR300 sample, the basal poles of only ∼52% of the DRXed grains are distributed within 30° from the ND. This result implies that as the rolling temperature increases, the basal planes of the DRXed grains gradually align parallel to the rolling plane. The tilting of the basal texture toward the RD of the HSR300 sample is caused by the inhomogeneous shear deformation during high-strain-rate rolling at a relatively low temperature of 300°C. However, the homogeneity of plastic deformation applied to the material during HSR increases with increasing rolling temperature, which finally leads to the generation of an ND basal texture that typically develops in Mg sheets hot-rolled at relatively low speeds.

Fig. 6.

(0002) Pole figures of unDRXed and DRXed regions and total region of HSR300, HSR350, and HSR400 samples.

(0.43MB).
Fig. 7.

Variations in area fraction of grains as a function of deviation angle of their basal pole from normal direction of rolling plane of HSRed samples.

(0.2MB).
4Conclusions

This study investigated the effects of rolling temperature on the microstructural and textural variations of an HSRed AZ31 alloy by performing hot rolling at a high speed of 470m/min at different temperatures: 300°C, 350°C, and 400°C. In all the HSRed samples, shear bands associated with localized inhomogeneous deformation were observed, but the density and intensity of the shear bands were found to decrease as the rolling temperature increased. The area fraction of the DRXed grains increased with increasing rolling temperature, which is attributed to the promotion of twin formation and TDRX behavior. With an increase in the rolling temperature from 300°C to 350°C, the average grain size of the HSRed samples decreased owing to a reduction in the area fraction of coarse unDRXed grains. However, with a further increase in the rolling temperature from 350°C to 400°C, this average grain size increased because of a significant increase in the DRXed grain size. Although all the samples exhibited a strong basal texture, the maximum texture intensity decreased with increasing rolling temperature because of a reduction in the area fraction of the unDRXed region, which has high texture intensities. In addition, as the rolling temperature decreased, the position with the maximum pole intensity in the DRXed region tilted from the ND toward the RD owing to the intensive shear deformation generated during the HSR process.

Conflicts of interest

The authors declare no conflicts of interest.

Acknowledgements

This research was supported by National Research Foundation of Korea (NRF) grants funded by the Korean Government (MSIP, South Korea) (Nos. 2016R1C1B2012140 and 2017R1A4A1015628).

References
[1]
W. Wang, W. Chen, W. Zhang, G. Cui, E. Wang.
Effect of deformation temperature on texture and mechanical properties of ZK60 magnesium alloy sheet by multi-pass lowered-temperature rolling.
Mater Sci Eng A, 712 (2018), pp. 608-615
[2]
M.R.G. Ferdowsi, M. Mazinani, G.R. Ebrahimi.
Effect of hot rolling and inter-stage annealing on the microstructure and texture evolution in a partially homogenized AZ91 magnesium alloy.
Mater Sci Eng A, 606 (2014), pp. 214-227
[3]
S.Q. Zhu, H.G. Yan, J.H. Chen, Y.Z. Wu, B. Su, Y.G. Du, et al.
Feasibility of high strain-rate rolling of a magnesium alloy across a wide temperature range.
Scr Mater, 67 (2012), pp. 404-407
[4]
J. Su, M. Sanjari, A.S.H. Kabir, I.-H. Jung, J.J. Jonas, S. Yue, et al.
Characteristics of magnesium AZ31 alloys subjected to high speed rolling.
Mater Sci Eng A, 636 (2015), pp. 582-592
[5]
H. Li, E. Hsu, J. Szpunar, H. Utsunomiya, T. Sakai.
Deformation mechanism and texture and microstructure evolution during high-speed rolling of AZ31B Mg sheets.
J Mater Sci, 43 (2008), pp. 7148-7156
[6]
S.Q. Zhu, H.G. Yan, J.H. Chen, Y.Z. Wu, J.Z. Liu, J. Tian.
Effect of twinning and dynamic recrystallization on the high strain rate rolling process.
Scr Mater, 63 (2010), pp. 985-988
[7]
M. Sanjari, A.S.H. Kabir, A. Farzadfar, H. Utsunomiya, E. Essadiqi, R. Petrov, et al.
Promotion of texture weakening in magnesium by alloying and thermomechanical processing. II: rolling speed.
J Mater Sci, 49 (2014), pp. 1426-1436
[8]
M. Sanjari, A. Farzadfar, A.S.H. Kabir, H. Utsunomiya, I.-H. Jung, R. Petrov, et al.
Promotion of texture weakening in magnesium by alloying and thermomechanical processing: (I) alloying.
J Mater Sci, 49 (2014), pp. 1408-1425
[9]
H. Asgari, J.A. Szpunar, A.G. Odeshi, L.J. Zeng, E. Olsson.
Experimental and simulation analysis of texture formation and deformation mechanism of rolled AZ31B magnesium alloy under dynamic loading.
Mater Sci Eng A, 618 (2014), pp. 310-322
[10]
M. Sanjari, S.A. Farzadfar, H. Utsunomiya, T. Sakai, E. Essadiqi, S. Yue.
High speed rolling of Mg–3Al–1Zn alloy: texture and microstructure analysis.
Mater Sci Technol, 28 (2012), pp. 928-933
[11]
J.H. Lee, J.U. Lee, S.H. Kim, S.W. Song, C.S. Lee, S.H. Park.
Dynamic recrystallization behavior and microstructural evolution of Mg alloy AZ31 through high-speed rolling.
J Mater Sci Technol, 34 (2018), pp. 1747-1755
[12]
H. Yu, Y.M. Kim, B.S. You, H.S. Yu, S.H. Park.
Effects of cerium addition on the microstructure, mechanical properties and hot workability of ZK60 alloy.
Mater Sci Eng A, 559 (2013), pp. 798-807
[13]
Y.B. Chun, C.H.J. Davies.
Texture effects on development of shear bands in rolled AZ31 alloy.
Mater Sci Eng A, 556 (2012), pp. 253-259
[14]
A. Galiyev, R. Kaibyshev, G. Gottstein.
Correlation of plastic deformation and dynamic recrystallization in magnesium alloy ZK60.
Acta Mater, 49 (2001), pp. 1199-1207
[15]
J. Su, S. Kaboli, A.S.H. Kabir, I. Jung, S. Yue.
Effect of dynamic precipitation and twinning on dynamic recrystallization of micro-alloyed Mg–Al–Ca alloys.
Mater Sci Eng A, 587 (2013), pp. 27-35
[16]
C. Bettles, M. Barnett.
Advances in wrought magnesium alloys: fundamentals of processing, properties and applications.
Woodhead Publishing, (2012),
[17]
G. Hamada, T. Sakai, H. Utsunomiya.
Effect of rolling speed on deformability and microstructure in rolling of AZ31B magnesium alloy.
Adv Mater Res, 89–91 (2010), pp. 227-231
[18]
J.W. Christian, S. Mahajan.
Deformation twinning.
Progr Mater Sci, 39 (1995), pp. 1-157
[19]
L.E. Murr, E.V. Esquivel.
Observations of common microstructural issues associated with dynamic deformation phenomena: twins, microbands, grain size effects, shear bands, and dynamic recrystallization.
J Mater Sci, 39 (2004), pp. 1153-1168
Copyright © 2019. The Authors
Journal of Materials Research and Technology

Subscribe to our newsletter

Article options
Tools
Cookies policy
To improve our services and products, we use cookies (own or third parties authorized) to show advertising related to client preferences through the analyses of navigation customer behavior. Continuing navigation will be considered as acceptance of this use. You can change the settings or obtain more information by clicking here.