Effect of temperature of DSR on RT(室温) mechanical properties and texture in an AZ31 alloy

Journal of Materials Processing Technology182(2007)

644–647

Short communication

Effect of temperature of differential speed rolling on room temperature mechanical properties and texture in an AZ31magnesium alloy

Hiroyuki Watanabe?,Toshiji Mukai,Koichi Ishikawa

Osaka Municipal Technical Research Institute,1–6–50Morinomiya,Joto-ku,Osaka536–8553,Japan

Received5January2004;received in revised form20July2006;accepted2August2006

Abstract

Differential speed rolling(DSR)was applied to the AZ31magnesium alloy,intended to modify the texture and thus to enhance the room temperature ductility.Especially,effect of DSR temperature on resulting room temperature tensile properties and texture was investigated at a ?xed rolling speed ratio of1.1.The strength was not affected by the rolling temperature:the yield strength and the ultimate tensile strength for all materials processed by DSR were approximately240and290MPa,respectively.On the other hand,elongation-to-failure increased from13.6 to18.5%with decreasing rolling temperature from573to473K.In addition,the material processed by DSR exhibited approximately1.5times larger ductility than that by conventional symmetric rolling at a rolling temperature of473K.The DSR at523and473K resulted in the basal plane orientation at the position inclined by～5and8?from the normal direction toward the rolling direction,respectively.It was suggested that the higher ductility of the material processed at lower temperatures is attributed to the slight change in the basal plane orientation and/or reduction in grain size.

?2006Elsevier B.V.All rights reserved.

Keywords:Magnesium alloy;Asymmetric rolling;Differential speed rolling;Mechanical properties;Texture

1.Introduction

Die casting and semi-solid processing of thixotropic molding has been a principal technique for the fabrication of magnesium alloys because of its high productivity,suitable strength,quality and dimensional control.However,magnesium alloy fabrica-tion by plastic forming also has considerable potential[1–6] because the alloys have higher ductility and strength than the castings,and because plastic forming enables high productivity and superior mechanical properties.At present,plastic forming of magnesium alloy sheets by deep drawing has been adopted as a secondary processing in fabricating several electric appliance housings[7].

Formability in the secondary processing strongly depends on the orientation of basal plane in magnesium alloys,because the critical resolved shear stresses for the non-basal slips are much higher than that for the basal slip near the room temperature [8].Primary processing,such as hot rolling and hot extrusion generally gives rise to a strong basal texture[9–12],and this leads ?Corresponding author.Tel.:+81669638149;fax:+81669638145.

E-mail address:hwata@omtri.city.osaka.jp(H.Watanabe).to very limited ductility near the room temperature.Therefore, texture control during primary processing is important in order to enhance the formability in the secondary processing.

Mukai et al.[13]succeeded in greatly enhancing the room temperature ductility in an AZ31magnesium alloy by adopting equal-channel angular extrusion method,which could introduce shear strain inclined to～45?against the extrusion.On the other hand,it is expected that an asymmetric rolling,such as single roller drive rolling(SRDR)[14,15]and differential speed rolling (DSR)[16,17],can also introduce the shear strain[18].The SRDR has already been applied for the AZ31magnesium alloy [19].It has been shown that the SRDR is effective to change the orientation of basal plane in the rolling plane and to enhance the press formability compared with normal(symmetric)rolling. These results suggest that the peculiar texture development is associated with the introduction of the shear strain during pri-mary processing.

Very recently,Yoshida et al.[20]showed that the texture development after4-pass ECAE depends on the working temper-ature in AZ31alloy.When the material was processed at573K, the majority of basal plane oriented parallel to the extruded direc-tion.On the other hand,when the material was processed at lower temperatures of523or473K,the basal plane was inclined at45?

0924-0136/$–see front matter?2006Elsevier B.V.All rights reserved. doi:10.1016/j.jmatprotec.2006.08.010

H.Watanabe et al./Journal of Materials Processing Technology182(2007)644–647645

to the extrusion direction.This indicates that the temperature for shear deformation is very important to control the texture.

The DSR is more controllable and reproducible process com-pared with SRDR,and thus useful method from the industrial point of view.Effect of rolling direction during DSR in AZ31 alloy has been reported elsewhere by the present authors[21]. In the present study,the effect of DSR temperature on the resulting microstructure,texture and mechanical properties was examined.

2.Experimental

The material used in the present study was a commercial Mg–Al–Zn alloy, AZ31.A hot extruded plate with a thickness of6.35mm was received from Osaka Fuji Corp,Japan.The as-received material had both coarse and?ne grains with the size of100and20?m,respectively.The(0002)pole?gure of as-received material has been reported elsewhere[21].The as-received material had texture typically observed in extruded magnesium[11]:the majority of basal plane oriented parallel to the extruded direction,though the slight distribution to the plate width direction was observed.

The conventional symmetrical rolling was carried out to a sheet thickness of1.0mm at a specimen pre-heating temperature of523K and at a roll sur-face temperature of383K under a rolling speed of2.0m/min.The roll surface was lubricated by oil to prevent the adhesion of magnesium to the roll sur-face.The specimens were?rst pre-heated for5min to assure through heating. Between each pass,the specimens were pre-heated for3min.The rolling was performed with a reduction of approximately20%per pass.Immediately after the rolling,the specimen was annealed at523K for3min,and then cooled in air.

The DSR was applied to the above mentioned symmetrically rolled sheets. The pre-heating temperatures for DSR were473,523and573K.The spec-imens were pre-heated for5min.The DSR was performed only once to the ?nal sheet thickness of0.85mm.The rolling speed of upper and lower rolls was2.2and2.0m/min,respectively.For comparison,symmetric rolling was also performed at a rolling temperature of473K and at a rolling speed of 2.0m/min.

Before the tensile tests and texture analysis,the specimens were annealed at 423K for1h under a weight pressure of4×10?3MPa to straighten the rolled sheets.

X-ray texture analysis was performed by the Schulz refection method atα-angles ranging from15to90?.The(0002)pole?gures were measured at the mid-layer of the rolling plane for all specimens.

Tensile specimens had tensile axes parallel to the rolling direction.The spec-imens had a parallel length of30mm,width of5mm and thickness of0.85mm. Tensile tests were carried out at room temperature and at an initial strain rate of 5×10?4s?1.The strain was measured by extensometer with the gauge length of25mm.Yield strength(0.2%proof strength),ultimate tensile strength and elongation-to-failure were calculated.

3.Results and discussion

Optical microstructures in the rolling plane for materials pro-cessed by(a)symmetric rolling at473K,(b)DSR at473K,(c) DSR at523K and(d)DSR at573K are shown in Fig.1.After the hot rolling,the grains were?ner than that of as-received material:grains were re?ned to be smaller than20?m for all materials.The grain size decreased with decreasing rolling tem-perature.The extent of?ne-grained region was slightly larger in the material processed by DSR at473K than in the material pro-cessed by symmetric rolling at the same temperature.Hot rolled materials had equiaxed grains,indicating that recrystallization took place during rolling.Deformation twins were observed for all

materials.Fig.1.Optical microstructures in the rolling plane for(a)symmetrically rolled sheet at473K,(b)asymmetrically rolled sheet at473K,(c)asymmetrically rolled sheet at523K and(d)asymmetrically rolled sheet at573K.

646H.Watanabe et al./Journal of Materials Processing Technology 182(2007)

644–647

Fig.2.(0002)pole ?gures of (a)symmetrically rolled sheet at 473K,(b)asymmetrically rolled sheet at 473K,(c)asymmetrically rolled sheet at 523K and (d)asymmetrically rolled sheet at 573K.

The (0002)pole ?gures of materials processed by (a)sym-metric rolling at 473K,(b)DSR at 473K,(c)DSR at 523K and (d)DSR at 573K are shown in Fig.2.The symmetrically rolled material tended to show a double peak inclined to the rolling direction.The distribution was symmetric to the rolling direction.The material processed by DSR at 573K had also symmetric basal plane distribution.On the other hand,the mate-rials processed by DSR at 523and 473K showed (0002)pole density at the position inclined by ～5and 8?from the normal direction toward the rolling direction,respectively.The extent of inclination in the material processed by DSR at 473K is higher than that by DSR at 523K.It is interesting to note that the distribution was not symmetric to the rolling direction in the material processed by DSR at 473or 523K.Chino et al.[19]reported similar texture in AZ31processed by SRDR,whose (0002)pole density inclined 10?from the normal direction toward the rolling direction.The inclination may be related to the different mode of loading:larger shear strain is introduced during DSR compared with normal symmetric rolling even in the mid-layer.

Mechanical properties of materials processed by symmetric rolling and DSR are shown in Fig.3.All materials processed by DSR exhibited similar yield strength of ～240MPa.The yield strength of symmetrically rolled material was higher than that of asymmetrically rolled materials by ～15MPa.The ultimate ten-sile strength was ～290MPa for all materials.In general,strength of polycrystalline materials increases with decreasing grain size.In addition,it has been pointed out that the contribution of grain re?nement to the strength is signi?cant in magnesium alloys with h.c.p.structure [22].Though the grain size of materials processed by DSR decreased with decreasing rolling tempera-

ture,all materials exhibited similar yield strength of ～240MPa.On the other hand,magnesium alloys can be strengthened by introducing the strong basal texture parallel to the tensile direc-tion [10,23].It is expected that the inclination of the basal plane in the material processed by DSR at lower temperatures would decrease the contribution of strengthening by texture.As a result,strength did not increase with decreasing grain size in the mate-rials processed by DSR.

The elongation-to-failure,δ,depended on the rolling temper-ature in the materials processed by DSR:the ductility

increased

Fig.3.Room temperature tensile properties of AZ31sheets processed by sym-metric and asymmetric rolling.

H.Watanabe et al./Journal of Materials Processing Technology182(2007)644–647647

with decreasing rolling temperature.In addition,it is noted that the ductility of material processed by DSR at473K was higher than that processed by symmetric rolling at the same tempera-ture.The DSR is suggested to be effective to enhance the room temperature ductility in AZ31magnesium alloy compared with conventional symmetric rolling.The ductility enhancement is probably associated with the slight change in the basal texture [21]and/or reduction in grain size[22].

4.Summary

Differential speed rolling(DSR)was applied to the AZ31 magnesium alloy in order to modify the texture,and thus enhance the room temperature ductility.Especially,effect of rolling tem-perature on texture and room temperature tensile properties was investigated.The DSR was performed only at once at tempera-tures of473,523and573K and a rolling speed ratio of1.1using commercial extruded plate.The results are as follows:

(1)The grain sizes after rolling were re?ned for all materials.

The grain size decreased with decreasing rolling tempera-ture.The extent of?ne-grained region was slightly larger in the material processed by DSR at473K than in the material processed by symmetric rolling at the same temperature.

(2)The materials processed by symmetric rolling at473K and

DSR at573K showed the symmetric basal plane distribu-tion to the rolling direction.On the other hand,the materials processed by DSR at523and473K showed(0002)pole density at the position inclined by～5and8?from the nor-mal direction toward the rolling direction,respectively.The basal plane distribution was not symmetric to the rolling direction in the materials processed by DSR at473or523K.

(3)The yield strength and the ultimate tensile strength for all

materials processed by DSR were approximately240and 290MPa,respectively.The similar strength was suggested to be a result of the counterbalance between grain re?nement strengthening and texture softening.

(4)The elongation-to-failure increased from13.6to18.5%with

decreasing rolling temperature from573to473K.In addi-tion,it was noted that only1-pass DSR effectively enhanced the room temperature ductility:the material processed by DSR exhibited approximately1.5times larger ductility than that by symmetric rolling at a rolling temperature of473K.

The ductility enhancement is probably associated with the slight change in the basal texture and/or reduction in grain size.

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一般过去式 时间状语：yesterday just now (刚刚) the day before three days ag0 a week ago in 1880 last month last year 1. I was in the classroom yesterday. I was not in the classroom yesterday. Were you in the classroom yesterday. 2. They went to see the film the day before. Did they go to see the film the day before. They did go to see the film the day before. 3. The man beat his wife yesterday. The man didn’t beat his wife yesterday. 4. I was a high student three years ago. 5. She became a teacher in 2009. 6. They began to study english a week ago 7. My mother brought a book from Canada last year. 8.My parents build a house to me four years ago . 9.He was husband ago. She was a cooker last mouth. My father was in the Xinjiang half a year ago. 10.My grandfather was a famer six years ago. 11.He burned in 1991

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M A: Has the case been closed yet? B: No, the magistrate still needs to decide the outcome. magistrate n.地方行政官，地方法官，治安官 A: I am unable to read the small print in the book. B: It seems you need to magnify it. magnify vt.１．放大，扩大；２．夸大，夸张 A: That was a terrible storm. B: Indeed, but it is too early to determine the magnitude of the damage. magnitude n.１．重要性，重大；２．巨大，广大 A: A young fair maiden like you shouldn’t be single. B: That is because I am a young fair independent maiden. maiden n.少女，年轻姑娘，未婚女子 a.首次的，初次的 A: You look majestic sitting on that high chair. B: Yes, I am pretending to be the king! majestic a.雄伟的，壮丽的，庄严的，高贵的 A: Please cook me dinner now. B: Yes, your majesty, I’m at your service. majesty n.１．［Ｍ－］陛下（对帝王，王后的尊称）；２．雄伟，壮丽，庄严 A: Doctor, I traveled to Africa and I think I caught malaria. B: Did you take any medicine as a precaution? malaria n.疟疾 A: I hate you! B: Why are you so full of malice? malice n.恶意，怨恨 A: I’m afraid that the test results have come back and your lump is malignant. B: That means it’s serious, doesn’t it, doctor? malignant a.１．恶性的，致命的；２．恶意的，恶毒的 A: I’m going shopping in the mall this afternoon, want to join me? B: No, thanks, I have plans already. mall n.（由许多商店组成的）购物中心 A: That child looks very unhealthy. B: Yes, he does not have enough to eat. He is suffering from malnutrition.

base on的例句

意见应以事实为根据. 3 来自辞典例句 192. The bombers swooped ( down ) onthe air base. 轰炸机 突袭 空军基地. 来自辞典例句 193. He mounted their engines on a rubber base. 他把他们的发动机装在一个橡胶垫座上. 14 来自辞典例句 194. The column stands on a narrow base. 柱子竖立在狭窄的地基上. 14 来自辞典例句 195. When one stretched it, it looked like grey flakes on the carvas base. 你要是把它摊直, 看上去就象好一些灰色的粉片落在帆布底子上. 18 来自辞典例句 196. Economic growth and human well - being depend on the natural resource base that supports all living systems. 经济增长和人类的福利依赖于支持所有生命系统的自然资源. 12 1 来自辞典例句 197. The base was just a smudge onthe untouched hundred - mile coast of Manila Bay. 那基地只是马尼拉湾一百英里长安然无恙的海岸线上一个硝烟滚滚的污点. 6 来自辞典例句 198. You can't base an operation on the presumption that miracles are going to happen. 你不能把行动计划建筑在可能出现奇迹的假想基础上.

英语造句大全

英语造句大全English sentence 在句子中，更好的记忆单词！ 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character. （2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n.

(完整版)主谓造句

主语+谓语 1. 理解主谓结构 1) The students arrived. The students arrived at the park. 2) They are listening. They are listening to the music. 3) The disaster happened. 2．体会状语的位置 1) Tom always works hard. 2) Sometimes I go to the park at weekends.. 3) The girl cries very often. 4) We seldom come here. The disaster happened to the poor family. 3. 多个状语的排列次序 1) He works. 2) He works hard. 3) He always works hard. 4) He always works hard in the company. 5) He always works hard in the company recently. 6) He always works hard in the company recently because he wants to get promoted. 4. 写作常用不及物动词 1. ache My head aches. I’m aching all over. 2. agree agree with sb. about sth. agree to do sth. 3. apologize to sb. for sth. 4. appear (at the meeting, on the screen) 5. arrive at / in 6. belong to 7. chat with sb. about sth. 8. come (to …) 9. cry 10. dance 11. depend on /upon 12. die 13. fall 14. go to … 15. graduate from 16. … happen 17. laugh 18. listen to... 19. live 20. rise 21. sit 22. smile 23. swim 24. stay (at home / in a hotel) 25. work 26. wait for 汉译英： 1.昨天我去了电影院。 2.我能用英语跟外国人自由交谈。 3.晚上7点我们到达了机场。 4.暑假就要到了。 5.现在很多老人独自居住。 6.老师同意了。 7.刚才发生了一场车祸。 8.课上我们应该认真听讲。9. 我们的态度很重要。 10. 能否成功取决于你的态度。 11. 能取得多大进步取决于你付出多少努力。 12. 这个木桶能盛多少水取决于最短的一块板子的长度。

初中英语造句

【it's time to和it's time for】 ——————这其实是一个句型,只不过后面要跟不同的东西. ——————It's time to跟的是不定式（to do）.也就是说,要跟一个动词,意思是“到做某事的时候了”.如： It's time to go home. It's time to tell him the truth. ——————It's time for 跟的是名词.也就是说,不能跟动词.如： It's time for lunch.(没必要说It's time to have lunch) It's time for class.(没必要说It's time to begin the class.) They can't wait to see you Please ask liming to study tonight. Please ask liming not to play computer games tonight. Don’t make/let me to smoke I can hear/see you dance at the stage You had better go to bed early. You had better not watch tv It’s better to go to bed early It’s best to run in the morning I am enjoy running with music. With 表伴随听音乐 I already finish studying You should keep working. You should keep on studying English Keep calm and carry on 保持冷静继续前行二战开始前英国皇家政府制造的海报名字 I have to go on studying I feel like I am flying I have to stop playing computer games and stop to go home now I forget/remember to finish my homework. I forget/remember cleaning the classroom We keep/percent/stop him from eating more chips I prefer orange to apple I prefer to walk rather than run I used to sing when I was young What’s wrong with you There have nothing to do with you I am so busy studying You are too young to na?ve I am so tired that I have to go to bed early

The Kite Runner-美句摘抄及造句

《The Kite Runner》追风筝的人--------------------------------美句摘抄 1.I can still see Hassan up on that tree, sunlight flickering through the leaves on his almost perfectly round face, a face like a Chinese doll chiseled from hardwood: his flat, broad nose and slanting, narrow eyes like bamboo leaves, eyes that looked, depending on the light, gold, green even sapphire 翻译：我依然能记得哈桑坐在树上的样子，阳光穿过叶子，照着他那浑圆的脸庞。他的脸很像木头刻成的中国娃娃，鼻子大而扁平，双眼眯斜如同竹叶，在不同光线下会显现出金色、绿色，甚至是宝石蓝。 E.g.: A shadow of disquiet flickering over his face. 2.Never told that the mirror, like shooting walnuts at the neighbor's dog, was always my idea. 翻译：从来不提镜子、用胡桃射狗其实都是我的鬼主意。E.g.:His secret died with him, for he never told anyone. 3.We would sit across from each other on a pair of high

翻译加造句

一、翻译 1. The idea of consciously seeking out a special title was new to me., but not without appeal. 让我自己挑选自己最喜欢的书籍这个有意思的想法真的对我具有吸引力。 2.I was plunged into the aching tragedy of the Holocaust, the extraordinary clash of good, represented by the one decent man, and evil. 我陷入到大屠杀悲剧的痛苦之中，一个体面的人所代表的善与恶的猛烈冲击之中。 3.I was astonished by the the great power a novel could contain. I lacked the vocabulary to translate my feelings into words. 我被这部小说所包含的巨大能量感到震惊。我无法用语言来表达我的感情（心情）。 4，make sth. long to short长话短说 5.I learned that summer that reading was not the innocent(简单的) pastime(消遣) I have assumed it to be., not a breezy, instantly forgettable escape in the hammock(吊床)，( though I’ ve enjoyed many of those too ). I discovered that a book, if it arrives at the right moment, in the proper season, will change the course of all that follows. 那年夏天，我懂得了读书不是我认为的简单的娱乐消遣，也不只是躺在吊床上，一阵风吹过就忘记的消遣。我发现如果在适宜的时间、合适的季节读一本书的话，他将能改变一个人以后的人生道路。 二、词组造句 1. on purpose 特意，故意 This is especially true here, and it was ~. (这一点在这里尤其准确，并且他是故意的) 2.think up 虚构，编造，想出 She has thought up a good idea. 她想出了一个好的主意。 His story was thought up. 他的故事是编出来的。 3. in the meantime 与此同时 助记：in advance 事前in the meantime 与此同时in place 适当地... In the meantime, what can you do? 在这期间您能做什么呢？ In the meantime, we may not know how it works, but we know that it works. 在此期间，我们不知道它是如何工作的，但我们知道，它的确在发挥作用。 4.as though 好像，仿佛 It sounds as though you enjoyed Great wall. 这听起来好像你喜欢长城。 5. plunge into 使陷入 He plunged the room into darkness by switching off the light. 他把灯一关，房

改写句子练习2标准答案

The effective sentences:(improve the sentences!) 1.She hopes to spend this holiday either in Shanghai or in Suzhou. 2.Showing/to show sincerity and to keep/keeping promises are the basic requirements of a real friend. 3.I want to know the space of this house and when it was built. I want to know how big this house is and when it was built. I want to know the space of this house and the building time of the house. 4.In the past ten years,Mr.Smith has been a waiter,a tour guide,and taught English. In the past ten years,Mr.Smith has been a waiter,a tour guide,and an English teacher. 5.They are sweeping the floor wearing masks. They are sweeping the floor by wearing masks. wearing masks,They are sweeping the floor. 6.the drivers are told to drive carefully on the radio. the drivers are told on the radio to drive carefully 7.I almost spent two hours on this exercises. I spent almost two hours on this exercises. 8.Checking carefully,a serious mistake was found in the design. Checking carefully,I found a serious mistake in the design.

用以下短语造句

M1 U1 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： add up (to) be concerned about go through set down a series of on purpose in order to according to get along with fall in love (with) join in have got to hide away face to face 1 We’ve chatted online for some time but we have never met ___________. 2 It is nearly 11 o’clock yet he is not back. His mother ____________ him. 3 The Lius ___________ hard times before liberation. 4 ____________ get a good mark I worked very hard before the exam. 5 I think the window was broken ___________ by someone. 6 You should ___________ the language points on the blackboard. They are useful. 7 They met at Tom’s party and later on ____________ with each other. 8 You can find ____________ English reading materials in the school library. 9 I am easy to be with and _____________my classmates pretty well. 10 They __________ in a small village so that they might not be found. 11 Which of the following statements is not right ____________ the above passage? 12 It’s getting dark. I ___________ be off now. 13 More than 1,000 workers ___________ the general strike last week. 14 All her earnings _____________ about 3,000 yuan per month. 二.用以下短语造句： 1.go through 2. no longer/ not… any longer 3. on purpose 4. calm… down 5. happen to 6. set down 7. wonder if 三. 翻译： 1.曾经有段时间，我对学习丧失了兴趣。（there was a time when…） 2. 这是我第一次和她交流。（It is/was the first time that …注意时态） 3.他昨天公园里遇到的是他的一个老朋友。（强调句） 4. 他是在知道真相之后才意识到错怪女儿了。（强调句） M 1 U 2 一. 把下列短语填入每个句子的空白处（注意所填短语的形式变化）： play a …role (in) because of come up such as even if play a …part (in) 1 Dujiangyan(都江堰) is still ___________in irrigation(灌溉) today. 2 That question ___________ at yesterday’s meeting. 3 Karl Marx could speak a few foreign languages, _________Russian and English. 4 You must ask for leave first __________ you have something very important. 5 The media _________ major ________ in influencing people’s opinion s. 6 _________ years of hard work she looked like a woman in her fifties. 二.用以下短语造句： 1.make (good/full) use of 2. play a(n) important role in 3. even if 4. believe it or not 5. such as 6. because of

英语造句

English sentence 1、(1)、able adj. 能 句子：We are able to live under the sea in the future. (2)、ability n. 能力 句子：Most school care for children of different abilities. (3)、enable v. 使。。。能 句子：This pass enables me to travel half-price on trains. 2、(1)、accurate adj. 精确的 句子：We must have the accurate calculation. (2)、accurately adv. 精确地 句子：His calculation is accurately. 3、(1)、act v. 扮演 句子：He act the interesting character.（2）、actor n. 演员 句子：He was a famous actor. (3)、actress n. 女演员 句子：She was a famous actress. (4)、active adj. 积极的 句子：He is an active boy. 4、add v. 加 句子：He adds a little sugar in the milk. 5、advantage n. 优势 句子：His advantage is fight. 6、age 年龄n. 句子：His age is 15. 7、amusing 娱人的adj. 句子：This story is amusing. 8、angry 生气的adj. 句子：He is angry. 9、America 美国n. 句子：He is in America. 10、appear 出现v. He appears in this place. 11. artist 艺术家n. He is an artist. 12. attract 吸引 He attracts the dog. 13. Australia 澳大利亚 He is in Australia. 14.base 基地 She is in the base now. 15.basket 篮子 His basket is nice. 16.beautiful 美丽的 She is very beautiful. 17.begin 开始 He begins writing. 18.black 黑色的 He is black. 19.bright 明亮的 His eyes are bright. 20.good 好的 He is good at basketball. 21.British 英国人 He is British. 22.building 建造物 The building is highest in this city 23.busy 忙的 He is busy now. 24.calculate 计算 He calculates this test well. 25.Canada 加拿大 He borns in Canada. 26.care 照顾 He cared she yesterday. 27.certain 无疑的 They are certain to succeed. 28.change 改变 He changes the system. 29.chemical 化学药品