Faculty Profiles - OKAYASU Mitsuhiro

Papers - OKAYASU Mitsuhiro

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Domain switching behavior in lead zirconate titanate piezoelectric ceramics

Mitsuhiro Okayasu, Kohei Bamba

Scripta Materialia 146 272 - 275 2018.3

Language：English Publishing type：Research paper (scientific journal) Publisher：PERGAMON-ELSEVIER SCIENCE LTD

The domain switching behaviors of lead zirconate titanate ceramics were monitored via direct, in-situ lattice observation using transmission electron microscopy. The lattice structures were monitored via video as a sample was heated from room temperature to 300 degrees C. The lattices vibrated in the [110] direction several times over a short period, e.g., 0.1 s. Moreover, lattice sliding occurred in the [100] direction for about 15 A. Those lattice motions were detected at around 83-84 degrees C. Lattice orientations were analyzed using the domain switching model to substantiate whether these movements can be attributed to domain switching. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.scriptamat.2017.12.003

Mechanical properties of the riveted connecting forming of CFRP plates

Mitsuhiro Okayasu, Ryo Naito

International Journal of Material Forming 11 ( 2 ) 225 - 232 2018.3

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER FRANCE

Mechanical properties of the unidirectional CFRP sheets connected by various rivet formations are experimentally investigated to propose the suitable riveted connection of the CFRP sheets. In this approach, the rivet connection is conducted with different position and different number. The connecting strength is dependent on the fracture mode. In basic, two different fracture modes are obtained: rivet- and CFRP-based fracture, where the high and the low strength are obtained for the sample fractured mainly by rivet and CFRP, respectively. However, in addition to the two fracture modes, rivet failures with micro-crack in CFRP are detected. The micro-cracks make change of the stress-strain curve although, like the rivet fractured sample, the high strength is still obtained. The failure in CFRP is attributed to the fiber/matrix interfacial debonding. The failure characteristics of CFRP can be monitored during the shear loading test with variation of the electric current in the CFRP plates. The concept of this approach is to examine the change of the electric resistance due to the material failure. In this case, the decrement of the current value is related to the failure in the rivet and CFRP. With the rivet formation, the fracture mode is altered; and appropriate rivet positions are determined to make the high connecting strength of the CFRP plates.

DOI： 10.1007/s12289-017-1344-9

Effects of machined circular holes on the mechanical properties of unidirectional carbon fiber-reinforced plastics

Mitsuhiro Okayasu, Ryo Naito, Daisuke Fukuyama, Keiji Ogi

Journal of Composite Materials 52 ( 4 ) 465 - 474 2018.2

Language：English Publishing type：Research paper (scientific journal) Publisher：SAGE PUBLICATIONS LTD

The effects of machined circular holes on the mechanical properties and failure characteristics of a unidirectional CFRP were investigated. Our approach was to change the location and the number of holes: (i) a two-set hole was machined with different modes: (A) parallel, (B) 45 degrees and (C) a direction perpendicular to the loading direction; and (ii) multiple holes from n=0 to 5 were made in the sample parallel to the loading direction. The higher tensile and higher fatigue strengths were obtained for the CFRP sample produced by mode A, compared to modes B and C. This was attributed to the different extend of the maximum stress and stress distribution, caused by the geometrical effects on the sample. The ultimate tensile strength (sigma(UTS)) of the sample was well predicted by the geometrical criterion. If the number of holes was increased from n=0 to n=2, the tensile strength decreased dramatically. However, the tensile strength did not strongly decrease further for samples with multiple holes from n=2 to 5. The tensile strength is correlated with the maximum stress adjacent to the hole(s). Those stress values were verified by a 2D digital image correlation and a finite element analysis. Material failure of the CFRP during tensile loading was revealed by nondestructive testing using a piezoelectric ceramic, and debonding of the fibers occurred even at a low applied stress of approximately 35% sigma(UTS).

DOI： 10.1177/0021998317709331

Effect of thermal energy on 90° domain switching characteristics of piezoelectric ceramic

馬場康平, 岡安光博

日本機械学会論文集 84 ( 863 ) 2018

Corrosion characteristics of a tungsten alloy die-casting mould material in molten aluminium alloy

Mitsuhiro Okayasu, Lele Yang

International Journal of Cast Metals Research 31 ( 3 ) 162 - 168 2018

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

To understand the corrosion characteristics of W90 tungsten alloy and compare them with those of conventional hot-worked steel (SKD61), immersion tests were carried out in molten aluminium alloy (ADC12). Severe corrosion occurred in SKD61, whereas the corrosion resistance of W90 was about 40 times greater, with little occurring even after 300 h immersion. However, significant microstructural changes occurred in W90 resulting from penetration of aluminium and silicon through grain boundaries to create WAl5 and WSi2 phases, detectable even after a few hours' immersion. Relatively soft (hardness 1.5 GPa) WAl5 formed between the W based grains, and hard (10 GPa) WSi2 outside the W based grains. Tensile strength decreased slowly with increasing immersion time, while a significant reduction in fracture strain occurred. These changes in tensile properties were caused by the microstructural changes, e.g. soft and brittle intermetallic compounds. Crack propagated along the WAl5 phases (intergranular fracture), whereas transgranular fracture was dominant for uncorroded or less corroded W90.

DOI： 10.1080/13640461.2017.1405528

Experimentally and analyzed property of carbon fiber reinforced thermoplastic and thermoset plates

M. Okayasu, Y. Tsuchiya, H. Arai

Journal of Materials Science Research 7 ( 3 ) 12 - 21 2018

In situ TEM observations of microstructural characteristics of lead zirconate titanate piezoelectric ceramic during heating to 1000 degrees C

Mitsuhiro Okayasu, Tsukasa Ogawa, Yoshikazu Sasaki

CERAMICS INTERNATIONAL 43 ( 18 ) 16306 - 16312 2017.12

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

The microstructural characteristics of lead zirconate titanate (PZT) ceramic at high temperature were examined by in situ transmission electron microscopy (TEM) observations of lattice and microstructural formations. The PZT ceramic was heated from room temperature to 1000 degrees C using a compact heating device within the TEM. It was found that the microstructural characteristics of the ceramic changed significantly in various ways as the temperature was raised to 1000 degrees C. Domain-switching-like behavior was detected around 100 degrees C. Disordered lattice features such a dislocations disappeared owing to reduction in internal stress at temperatures above 300 degrees C. Heating to more than 800 degrees C for a certain period of time led to the formation of a nanocrystalline microstructure and to sublimation of Pb.

DOI： 10.1016/j.ceramint.2017.09.001

High Strength of Mg-9%Al-1%Zn Alloys Achieved by Severe Working

Mitsuhiro Okayasu, Takuya Muranaga

JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE 26 ( 10 ) 4977 - 4989 2017.10

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

To obtain the excellent mechanical properties of AZ91 magnesium alloy (Mg-8.9%Al-0.6%Zn-0.2%Mn), the microstructural characteristics of AZ91 alloys are modified by various forging and heating processes. High tensile properties (ultimate tensile strength sigma (UTS) = 420 MPa and fracture strain epsilon (f) = 3%) are obtained for the alloy made by the following process: solution treatment (ST) at 410 A degrees C for 24 h plus water quenching, multidirectional forging (MDF) with 5% strain applied in 15 forgings at room temperature, and warm unidirectional forging (WUF) at a forging rate of 75% at 225 A degrees C. The high tensile strength is a reflection of improved microstructural characteristics, namely a fine alpha-Mg phase and a high dislocation density. Moreover, brittle beta-phase is significantly attributed to the mechanical properties of AZ91 alloy. Because of the severe deformation undergone by the alloy during the MDF process, the solution treatment is important to achieve high ductility with low internal strain, i.e., normalization. In fact, the epsilon (f) value for the ST sample is as high as 10%, leading to severe work hardening during the tensile test, with deformation twins and slips. The WUF process is conducted immediately after the sample has been heated to 225 A degrees C, for less than 5 min, to avoid material softening. A relatively high tensile strength (sigma (UTS) = 305 MPa) is also achieved using the WUF process (with a forging rate of 75% at 200 A degrees C) after the ST and aging process (200 A degrees C for 12 h) although low ductility is found (epsilon (f) = 0.7%), with hard and brittle beta-phases being precipitated around the grain boundaries.

DOI： 10.1007/s11665-017-2944-8

Effects of 90 degrees domain switching on electric generation properties of PZT ceramic

Mitsuhiro Okayasu, Toshiki Yamasaki

Ceramics International 43 ( 4 ) 3590 - 3600 2017.3

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

The influence of domain switching on the electric generation properties of lead zirconate tinatate (PZT) ceramic has been investigated after static and cyclic loadings under various conditions. A PZT ceramic of size phi 8.0 mmx0.17 mm, consisting of a tetragonal lattice structure, i.e., c/a not equal 1.014, was used. Domain switching occurred as a result of the applied stress, where three different switching modes were employed: (I) simple 90 switching; (II) 90 switching with 90 rotation; and (III) 90 switching with 180 rotation. The rates of the switching mode were different: the simple switching mode (Mode I) was 20%; and both complicated switching modes (Mode II and III) were 40%. The extent of 90 domain switching was different depending on the grain and where the direction of the tetragonal structure (c-axis direction) was affected, e.g., the closer the parallel between the c-axis and the stress direction, the stronger the domain switching. The electric generation voltage increased with increasing applied cyclic stress; however, that voltage dropped suddenly as the stress value was close to its elastic limit. This is due to the 90 domain switching. Such domain switching (reduction of the electric voltage) occurred in the early cyclic stage.

DOI： 10.1016/j.ceramint.2016.11.196

Analysis of microstructural effects on mechanical properties of copper alloys

Mitsuhiro Okayasu, Takuya Muranaga, Ayana Endo

Journal of Science-Advanced Materials and Devices 2 ( 1 ) 128 - 139 2017.3

Language：English Publishing type：Research paper (scientific journal) Publisher：VIETNAM NATL UNIV

With the aim of obtaining copper alloys with favorable mechanical properties (high strength and high ductility) for various engineering applications, the microstructural characteristics of two conventional copper alloys - an aluminum bronze (AlBC; Cu-Al-9.3-Fe-3.8-Ni-2-Mn-0.8) and a brass (HB: Cu-Al-4-Zn-25-Fe-3-Mn-3.8) - and a recently developed aluminum bronze (CADZ: Cu-Al-10.5-Fe-3.1-Ni-3.5-Mn-1.1-Sn-3.7), were controlled by subjecting the alloys to two different processes (rolling and casting) under various conditions. For the rolling process, the rolling rate and temperature were varied, whereas for the casting process, the solidification rate was varied. Microstructural characteristics, as examined by electron backscatter diffraction analysis, were found to differ among the alloys. Complicated microstructures formed in CADZ led to high hardness and high tensile strength (sigma(UTS)), but low ductility (epsilon(f)). For CADZ, casting at a high solidification rate allowed an increase in ductility to be obtained as a result of fine-grained structure and low internal stress. In contrast, high ductility (with a fracture strain of more than 30%) was found for both cast AlBC and cast HB; moreover, both of these alloys possessed high tensile strength when produced by warm rolling at 473 K. For CADZ, on the other hand, no clear effect of rolling on tensile strength could be found, owing to the many microcracks caused by its brittleness. The results of this study indicate that copper alloys with excellent mechanical properties can be produced. This is especially the case for the conventional alloys, with a high tensile strength sigma(UTS) = 900 MPa and a high fracture strain epsilon(f) = 10% being obtained for warm-rolled brass. (C) 2016 The Authors. Publishing services by Elsevier B.V. on behalf of Vietnam National University, Hanoi. This is an open access article under the CC BY license.

DOI： 10.1016/j.jsamd.2016.12.003

Effects of Oxide Scale on the Corrosion and Mechanical Properties for a High Speed Steel and a Graphite Cast Iron

Mitsuhiro Okayasu, Shaohua Wu

Oxidation of Metals 87 ( 1-2 ) 159 - 178 2017.2

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER/PLENUM PUBLISHERS

The mechanical properties and the oxidation characteristics of the high speed steel (HSS) for hot-rolling process, produced by centrifugal casting process, were investigated experimentally. Because of the complicated microstructure with tiny V-, Cr-, and W-based precipitations in the matrix, high hardness of the HSS samples was obtained. Moreover, high compressive strength and high compressive strain were detected, while low tensile properties were obtained. In spite of the high hardness of HSS, the wear resistance was a low level due to severe oxidation on the HSS surface and generated cracks, but the wear resistance of HSS was still better than conventional graphite cast iron. Although the corrosion occurred by the wear test, no clear microstructural change was detected. Wear and corrosion characteristics were examined at high temperatures and high humidity using an originally proposed testing machine. With this testing machine, failure characteristics of HSS were clarified, in which the HSS sample was worn away easily due to the brittle oxidation scale during the rolling process, leading to the rough HSS surface. Furthermore, the low tensile strength of HSS made an acceleration of the failure especially crack growth. Such rough surface has made reduction in the quality of the rolled materials.

DOI： 10.1007/s11085-016-9663-7

Phase transformation system of austenitic stainless steels obtained by permanent compressive strain

Mitsuhiro Okayasu, Sai Tomida

Materials Science and Engineering A 684 712 - 725 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE SA

In order to understand more completely the formation of strain-induced martensite, phase structures were investigated both before and after plastic deformation, using austenitic stainless steels of various chemical compositions (carbon C=0.007-0.04 mass% and molybdenum Mo=0-2.10 mass%) and varying pre-strain levels (0-30%). Although the stainless steels consisted mainly of gamma austenite, two martensite structures were generated following plastic deformation, comprising epsilon and alpha' martensite. The martensitic structures were obtained in the twin deformation and slip bands. The severity of martensite formation (epsilon and alpha') increased with increasing C content. It was found that alpha' martensite was formed mainly in austenitic stainless steel lacking Mo, whereas a high Mo content led to a strong epsilon martensite structure, i.e. a weak alpha' martensite. The formation of alpha' martensite occurred from gamma austenite via e martensite, and was related to the slip deformation. Molybdenum in austenitic stainless steel had high slip resistance (or weak stress-induced martensite transformation), because of the stacking fault energy of the stainless steel affecting the austenite stability. This resulted in the creation of weak alpha' martensite. Models of the martensitic transformations gamma (fcc)-> epsilon (hcp)-> alpha' (bcc) were proposed on both the microscopic and nanoscopic scales. The alpha' martensite content of austenitic stainless steel led to high tensile strength; conversely, epsilon martensite had a weak effect on the mechanical strength. The influence of martensitic formation on the mechanical properties was evaluated quantitatively by statistical analysis.

DOI： 10.1016/j.msea.2016.12.101

Domain switching characteristics of lead zirconate titanate piezoelectric ceramics on a nanoscopic scale

Mitsuhiro Okayasu, Kohei Bamba

Journal of the European Ceramic Society 37 ( 1 ) 145 - 159 2017.1

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

Domain switching characteristics of lead zirconate titanate ceramics with and without poling under compressive loading are investigated using electron backscatter diffraction. For loading in the poling direction, the switching strain is stronger than that for loading perpendicular to the poling direction. There is strong domain switching when the domain (c-axis of the tetragonal structure) is orientated close to the loading direction. A large number of domains are switched between 85.4 degrees and 90.0 degrees, with many crossing the loading axis. Each grain consists of domains with three different patterns; i.e., with c-axis orientated in three directions in each grain. The patterns remain unchanged even with domain switching and strong deformation. However, the ratios among the patterns depend on compressive stress. Under stress, one or two specific domain modes are switched to about 90, although others are not switched as much. These domain switching characteristics are related to the poling and loading directions. 90 domain switching model is proposed on the basis of twin deformation model. Due to the aspect ratio of c/a = 1.014 (tetragonal structure), the angle of the switching is less than 90 degrees (89.2 degrees). This angle is corresponding to the switching angle obtained by an electron backscatter diffraction analysis (Ave. 88.9 degrees). (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jeurceramsoc.2016.07.034

Mechanical properties of Al-Si-Cu alloys produced by the continuous casting process with heating process

Mitsuhiro Okayasu, Shuhei Takeuchi, Toshihiro Ochi

International Journal of Cast Metals Research 30 ( 4 ) 217 - 225 2017

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

The mechanical properties of aluminium alloys produced by the continuous cast process and heating process (heat-cast-sample) were investigated, where the aluminium alloys are heated continuously to high temperatures for 1h immediately following heated mould continuous casting (HMC) and sand gravity casting (SGC). The material strength and ductility of the aluminium alloys were irregularly altered depending on the heating temperature. The mechanical properties decreased when the heating temperature increased to 400 degrees C and were then recovered when the temperature increased to 520 degrees C. However, these properties decreased again when heated to more than 540 degrees C. The mechanical properties of the HMC-heat-cast-sample showed overall higher than those for the SGC-sample. In addition to high tensile strength, high ductility was obtained for the HMC-520 degrees C samples compared with those for the as-cast-sample. Such changes were found to be directly attributable to the different severity of precipitate; moreover the crystal orientation was unchanged even after the heating process.

DOI： 10.1080/13640461.2017.1286556

A New Connecting Technology of Carbon Fiber Reinforced Plastic Plates

I.U. Hasanah, S. Baba, M. Okayasu

International Journal on Smart Material and Mechatronics 4 ( 1 ) 257 - 260 2017

Mechanical Properties of Magnesium Alloys Produced by the Heated Mold Continuous Casting Process

M. Okayasu, S. Wu, T. Tanimoto, S. Takeuchi

Archives of Foundry Engineering 16 ( 4 ) 208 - 216 2016.12

Publishing type：Research paper (scientific journal)

Investigation of the tensile and fatigue properties of cast magnesium alloys, created by the heated mold continuous casting process (HMC), was conducted. The mechanical properties of the Mg-HMC alloys were overall higher than those for the Mg alloys, made by the conventional gravity casting process (GC), and especially excellent mechanical properties were obtained for the Mg Y Zn -HMC alloy. This was because of the fine-grained structure composed of the α-Mg phases with the interdendritic LPSO phase. Such mechanical properties were similar levels to those for conventional cast aluminum alloy (Al Si Cu Fe Zn alloys: ADC12), made by the GC process. Moreover, the tensile properties (σ and ϵ ) and fatigue properties of the Mg Y Zn -HMC alloy were about 1.5 times higher than that for the commercial Mg Al Zn -GC alloy (AZ91). The high correlation rate between tensile properties and fatigue strength (endurance limit: σ ) was obtained. With newly proposed etching technique, the residual stress in the Mg Y Zn alloy could be revealed, and it appeared that the high internal stress was severely accumulated in and around the long-period stacking-order phases (LPSO). This was made during the solidification process due to the different shrinkage rate between α-Mg and LPSO. In this etching technique, micro-cracks were observed on the sample surface, and amount of micro-cracks (density) could be a parameter to determine the severity of the internal stress, i.e., a large amount to micro-cracks is caused by the high internal stress. 97 2 1 84.7 10.5 2.5 1.3 1 UTS f 97 2 1 90 9 1 l 97 2 1

DOI： 10.1515/afe-2016-0111

Mechanical properties of austenitic stainless steel with high niobium contents

M. Okayasu, S. Wu, K. Noda, D. Y. Lin, S. M. Yang

Materials Science and Technology (United Kingdom) 32 ( 13 ) 1382 - 1394 2016.9

Language：English Publishing type：Research paper (scientific journal) Publisher：TAYLOR & FRANCIS LTD

To better understand the influence of the microstructural characteristics on the mechanical properties of Fe-Cr -Ni -Nb austenitic stainless steel (ASS-Nb ), the mechanical properties were investigated. Nb addition was conducted with four different amounts: 0, 0.29, 0.58 and 0.86%. With the increasing Nb content, the mean grain size for the Fe-Cr-Ni-based alloys decreased, while the size of Nb precipitate increased. Owing to the different microstructural characteristics, their mechanical properties were altered. The highest tensile strength was obtained for ASS-Nb alloy. However, with the increasing Nb content in ASS-Nb alloys, the tensile strength decreases despite the grain refinement. The mechanical properties of the ASS-Nb alloys were influenced by the Nb precipitation hardening and the grain boundary cohesive strength, arising from the size of Nb precipitations. 22 25 x x 0.29 0.29–0.86

DOI： 10.1080/02670836.2015.1126431

A study of the electric power generation properties of a lead zirconate titanate piezoelectric ceramic

Mitsuhiro Okayasu, Keisuke Watanabe

Ceramics International 42 ( 12 ) 14049 - 14060 2016.9

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCI LTD

Electric power generation characteristics of lead zirconate titanate (PZT) piezoelectric ceramic have been investigated experimentally and numerically. A thin PZT ceramic plate attached to a thin brass plate was used to examine the electric voltage generated during cyclic loading. On increasing the number of PZT ceramic plates combined together in the longitudinal direction, the electric voltage increases with the highest electric voltage being obtained for four PZT ceramic plates; and the maximum electric voltage becomes almost constant even if the number of PZT ceramic plates combined together increases more than four. This is attributed to the low strain level and the mixed strain (compressive and tensile strain). The effect of strain characteristic on the electric voltage value was analyzed numerically using our strain definition, and a clear correlation between the extent of compressive strain and generated electric voltage is clarified. A different electric generation characteristic was further observed depending on the stress conditions: generation of positive and negative electric voltage occurs when the PZT ceramic is subjected to mainly compressive and tensile stress, respectively. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

DOI： 10.1016/j.ceramint.2016.06.012

Precise analysis of compressive strain effects on electric power generation properties of a lead zirconate titanate piezoelectric ceramic

Mitsuhiro Okayasu, Keisuke Watanabe

Journal of Advanced Ceramics 5 ( 1 ) 35 - 39 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGEROPEN

Electric power generation characteristics of lead zirconate titanate (PZT) piezoelectric ceramic have been examined during cyclic loading with different compressive strain value. A thin PZT ceramic plate attached to a thin brass plate was used. With an increasing compressive strain value in the PZT ceramic plate, the electric voltage increased, and the highest electric voltage was obtained for the sample with the high strain level (0.4%). The electric voltage decreased for the sample with more than 0.45% strain because of the failure in the PZT ceramic. The electric voltage was different depending on the strain condition, where the higher strain and the wider strain range (Delta epsilon) made the high electric voltage. Moreover, the electric voltage was attributed to the strain rate, where the higher strain rate made higher electric voltage due to high kinetic energy. The electric generation characteristics could be estimated with an operation of the strain value and strain ratio (epsilon(min)/epsilon(max)) especially for the sample loaded cyclically under the slow loading speed. This was affected by the linear correlation between the electric voltage and the strain value. Based upon the experimental work, suitable loading condition to make high electric voltage could be proposed.

DOI： 10.1007/s40145-015-0169-6

Effects of Sb, Sr, and Bi on the material properties of cast Al-Si-Cu alloys produced through heated mold continuous casting

Mitsuhiro Okayasu, Shuhei Takeuchi, Shaohua Wu, Toshihiro Ochi

Journal of Mechanical Science and Technology 30 ( 3 ) 1139 - 1147 2016.3

Language：English Publishing type：Research paper (scientific journal) Publisher：KOREAN SOC MECHANICAL ENGINEERS

Rare earth metals can create a fine eutectic Si structure in cast Al-Si-10.6-Cu-2.5 (ADC12) alloys produced through heated mold continuous casting. Fine and spherical eutectic Si phases are created in the ADC12 alloys through the addition of Sr0.04, and fine lamellar eutectic Si phases are created through Sb and Bi addition. Crystal orientation on the face perpendicular to the casting direction is formed by [110]; however, this uniform formation is collapsed in the ADC12 alloy with an increasing amount of Sr addition, such as Sr > 0.04%. The shape of the eutectic Si is statically analyzed, and the effects of the eutectic Si characteristics on the mechanical properties are examined experimentally. On the one hand, the mechanical properties of the ADC12-Sr alloy increase with increasing Sr content because of the fine eutectic Si, the randomly orientated crystal formation, and so on. On the other hand, the material ductility increases in the ADC12 alloy with increasing addition of Sb and Bi elements. A high fracture strain of approximately 14% is obtained for the ADC12-Bi1.5 alloy.

DOI： 10.1007/s12206-016-0218-2

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