Deformability and strengthening of superlight Mg-Li alloys

Deformability of Mg-Li alloys at room temperature and heat treatment characteristics of superlight Mg-8~30mass%Li alloys containing aluminum will be reviewed. Li addition enhances the deformability of magnesium. Particularly, the deformability of magnesium increases remarkably by the addition of lithium of more than 6mass%, which crystallizes lithium solid solution. Al, In or Ag addition to Mg-Li alloys leads to quenching hardenability due to solutionizing to 3 phase, and age hardening by spinodal decomposition into the additives+Li rich and poor phases from supersaturated solid solution. Alloying elements are solutionized to some extent and the growth of recrystallized grains is restricted by shortening the holding time at300°Cor350°C. Consequently, high strength and reasonable elongation can be obtained by such a heat treatment

Effect of Microstructural Factors on Tensile Properties of an ECAE-Processed AZ31 Magnesium Alloy * 1

Mg-3%Al-1%Zn (AZ31) alloy was subjected to ECAE (Equal Channel Angular Extrusion) processing under various processing conditions. Then tensile tests were carried out at room temperature to investigate the relationship between tensile properties and microstructural parameters that include grain size and the texture generated by ECAE processing. In 4-pass ECAE specimens processed at 523 K, tensile ductility is improved as a result of easy basal slip during tensile test along the extrusion direction, because such specimens have textures in which the basal plane is inclined at 45 to the extrusion direction. On the other hand, in the specimens processed at 573 K, 0.2% proof stress is higher than those of specimens processed at lower temperatures, but elongation is smaller. This is because of difficult basal slip caused by the textures in which the basal plane is oriented parallel to the extrusion direction. However, 8-pass specimens processed at 473 K and subsequently annealed, which have similar textures but different grain sizes (d), exhibit clear grain size dependencies of 0.2% proof stress ( 0:2 ) according to Hall-Petch relationship; 0:2 ¼ 30 þ 0:17d À1=2 . Therefore, crystallographic orientation has a profound effect on the tensile properties of AZ31 alloy, and grain size has a little effect

Interactive controller for audio object localization based on spatial representative vector operation

Abstract-In this paper, we propose a new interactive controller for audio object localization based on spatially representative vector operations on a stereo mixed source. First, we developed the interactive controller, which is equipped with a capacitive touchscreen panel so that the listener can intuitively operate audio objects displayed on the touchscreen panel with a touch pen. Next, we assessed the perceptual effects of localization and the sound quality of an audio object after performing individual operations to verify the operation of the interactive controller via a subjective evaluation. The results of the experiments clarify that the interactive controller enables the listener to change the gain and the localization of audio objects without sound degradation if the gain operation is not extreme

タテン オンバ セイギョ ト ハメン ゴウセイホウ ニ モトズク トウゴウガタ コウリョウイキ オンバ サイゲン ニ カンスル ケンキュウ

博士(Doctor)工学(Engineering)奈良先端科学技術大学院大学博第1044号甲第1044号博士(工学)奈良先端科学技術大学院大

Towards tailoring basal texture of rolled Mg alloy sheet by recrystallization for high room-temperature formability: A review

Room-temperature (RT) formability is a key factor to broaden the applications of rolled Mg alloy sheets in the industry. However, rolled Mg alloy sheets generally form strong basal texture, where the (0001) poles align parallel to the normal direction (ND). This hinders the activation of (0001) [112¯0] basal slip, limiting the RT formability. Therefore, texture weakening, i.e., the inclination of the (0001) poles from the ND, plays an important role to improve the RT formability. Recrystallization is crucial to control the textural development in Mg, and currently, the texture weakening is commonly achieved using static recrystallization (SRX). However, the type of slipping and twinning, which are activated during rolling, affect the textural features after SRX. It is also demonstrated that shear bands and preferential grain growth are important factors to tailor the texture during SRX. Indeed, dynamic recrystallization (DRX) easily occurs during rolling in Mg, which also affects the final rolling texture, while the effect of DRX on the textural formation is not extensively studied for the development of RT-formable Mg alloy sheets. Therefore, the effect of these factors on the textural development in rolled Mg is reviewed in this manuscript. Additionally, the ideal microstructure and texture for RT-formable Mg alloy sheets are still controversial. The RT-formability includes stretch forming (biaxial tension), bending (plane strain tension), and deep-drawing. In particular, the stretch forming is commonly used to evaluate the RT-formability of rolled Mg. Although the stretch formability has been improved by recent studies, the further improvement is necessary owing to the relatively low formability of rolled Mg compared with that of rolled Fe and Al. Based on the relationship between the microstructure/texture and stretch formability provided in the literature, the design guidance for high stretch formability is proposed in this review

Comparative Study on Directly-Aligned Multi-Point Controlled Wavefront Synthesis and Wave Field Synthesis

In this paper, we address a comparative study on Directly-Aligned Multi-Point Controlled Wavefront Synthesis (DMCWS) and Wave Field Synthesis (WFS) for realization of high-accuracy sound reproduction system, where amplitude, phase and attenuation characteristics of the wavefronts generated by DWCWS and WFS are assessed. First, in DMCWS, we can derive an optimal control line coordinate based on a numerical analysis. Next, the results of computer simulations reveal that the wavefront of DMCWS has wide availability in both spatial and frequency domains with few amplitude and phase errors, especially beyond the spatial aliasing frequency in WFS. Finally we can point out that the amplitude error of DMCWS has similar behavior to well-known spatial decay approximation expression of WFS; this implies an easiness in handling the amplitude error estimation of DMCWS. From these findings, we can conclude an advantageous position of DMCWS compared with WFS.APSIPA ASC 2009: Asia-Pacific Signal and Information Processing Association, 2009 Annual Summit and Conference. 4-7 October 2009. Sapporo, Japan. Poster session: Audio and Electroacoustics (5 October 2009)