• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    High temperature strain glass in Ti–Au and Ti–Pt based shape memory alloys*

    2021-01-21 02:15:22ShuaiRen任帥ChangLiu劉暢andWeiHuaWang汪衛(wèi)華
    Chinese Physics B 2021年1期
    關(guān)鍵詞:劉暢

    Shuai Ren(任帥), Chang Liu(劉暢), and Wei-Hua Wang(汪衛(wèi)華)

    1

    Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China

    2Frontier Institute of Science and Technology,State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China

    Keywords: shape memory alloys,martensitic transformation,strain glass,glass transition temperature

    1. Introduction

    Shape memory alloys (SMAs) are one of the most important smart materials that exhibit unique properties of the shape memory effect and superelasticity, due to a ferroelastic/martensitic transformation.[1]The two main SMA systems for current commercial applications are Ti–Ni-based and Cu-based alloys.[1]However,their martensitic transformation temperatures(Ms)are generally lower than 373 K,which limits the applications of SMAs in high temperature conditions.As a result, Ti–Au and Ti–Pt high temperature SMAs (HTSMAs)have received wide attention due to their high Ms.[2–4]

    Doping is an essential way to modify the martensitic transformation as well as the associated properties in SMAs.[5]However, doping usually introduces point defects into the SMAs, and thus further reduces the Ms. In recent years, it has been reported that when the martensitic transformation in SMAs is suppressed by excess doping, the system does not directly become nontransforming, but exhibits a novel glass transition.[6]As a result, the long-range strain ordered phase(i.e.,martensitic phase)is replaced by a short-range strain ordered glass state, which is termed as the “strain glass” given that the lattice strain is the order parameter of the martensitic transformation.[6]

    Strain glass is characterized by several typical features,such as no enthalpy change during the glass transition observed by differential scanning calorimetry(DSC),the disappearance of thermal hysteresis in electrical resistivity curves,and no breaking of the parent phase symmetry during the glass transition in the x-ray diffraction spectrums.[7]It also exhibits some important glass transition features, including the dynamic freezing measured by dynamic mechanical analysis (DMA) experiments and the breaking down of ergodicity measured by zero-field-cooling and field-cooling(ZFC/FC)experiments.[7]Moreover, the strain glass is of potential interest for applications, because it exhibits many interesting properties, such as the superelasticity of slim hysteresis,[8]stress tuned intelligent damping properties,[9]and low-fieldtriggered large magnetostriction.[10]Unfortunately, the glass transition temperature(Tg)of current strain glass alloys is generally lower than 273 K, which not only limits the potential applications of the strain glass,but also interrupts the investigation of the nature of strain glass as well.

    For example, the low glass transition temperature makes the experimental investigation of dynamic relaxation of strain glass difficult. Dynamic relaxation is an intrinsic feature of glasses, and exploring the dynamic relaxation of glasses is significant for understanding the nature of glasses.[11]The dynamic relaxation is generally measured by the DMA experiments,and the lower temperature limit of the DMA is around 130 K, as illustrated in Fig. 1. In metallic glass, thanks to their high Tg, several unique dynamic relaxation modes are observed, including primary α-relaxation, β-relaxation, and nearly constant loss, as illustrated in the loss modulus curve of a La55Ni20Al25bulk metallic glass(BMG)in Fig.1(a). In comparison, only one relaxation mode has been reported in strain glass up to now.[6,7]As shown in Fig. 1(b), there is a peak in the loss modulus curve of a Ti48.5Ni51.5strain glass alloy,close to the lower temperature limit of the DMA,which corresponds to the primary α-relaxation of the BMG.No other relaxation mode can be found except this peak,due to the low Tgof the strain glass.

    Fig. 1. Comparison of the loss modulus curve of (a) a La55Ni20Al25 bulk metallic glass(BMG)and(b)a Ti48.5Ni51.5 strain glass(STG)alloy, measured by the DMA experiment. The lower temperature limit is around 130 K.Above this limit,the BMG exhibits several relaxation modes in(a),including primary α-relaxation mode,β-relaxation mode,and nearly constant loss(NCL),while the strain glass only exhibits one α-relaxation mode in(b).

    In metallic glass, the β-relaxation has been well known as one of the intrinsic dynamic relaxation modes besides the α-relaxation,which corresponds to localized cooperative motions of a small number of atoms confined in loosely packed regions.[11]If strain glass possesses the same glassy dynamics as metallic glass,the β-relaxation should exist in the strain glass in principle. Therefore, the investigation of possible βrelaxation in strain glass may provide insight into the common dynamic characteristics of these two glasses, and deepen the understanding of the nature of strain glass. However, the investigation is interrupted due to the low Tgof current strain glass systems. As a result,it is of importance to discover high temperature strain glass systems.

    In Ti50Ni50xFexSMAs, the Tgof strain glass at x=6 is around 180 K,while the Msof the host alloy(i.e.,Ti50Ni50)is around 350 K.[12]On the other hand,in Ti50Pd50-xFexSMAs,the Tgof strain glass at x=14 is about 280 K,while the Msof the host alloy(i.e.,Ti50Pd50)is around 800 K.[13]The comparison between these two systems gives us a clue that the strain glass with high Tgcomes from high MsSMA systems. Therefore,we chose the two HTSMAs,Ti50Au50(Ms=893 K)and Ti50Pt50(Ms=1340 K),[2]as the host alloys and tried to find the strain glass in them. In this paper, we reported the strain glass with relatively high Tgfound in these two HTSMAs. In Ti50Au50-xCrxSMAs,strain glass appears at x=25,while in Ti50Pt50-yFeySMAs, strain glass takes place at y=30. Owing to the very high Msof the host alloys, these two systems both exhibit a relatively large ideal glass transition temperature(T0), which is comparable with the highest T0value reported until now.

    2. Experimental methods

    Samples of Ti50Au50-xCrx(x =15, 25, abbreviated by Crx hereafter) and Ti50Pt50-yFey(y=25, 30, abbreviated by Fey hereafter) alloys were prepared from highly pure metals(>99.95 at.%) by arc-melting under an argon atmosphere.The ingots were solution-treated at 1373 K for 12 h in evacuated quartz tubes,followed by water quenching. Then the ingots were cut into suitable shapes for different measurements.Latent heat of transformation was measured with a differential scanning calorimeter (DSC-Q200 from TA Company) with a cooling/heating rate of 10 K/min. Electrical resistivity (ER)of specimens was measured through a four-probe method with a constant current of 100 mA and a cooling/heating rate of 2 K/min. The anelasticity was detected by dynamic mechanical analysis(DMA-Q800 from TA Instruments)using a cooling rate of 2 K/min with a single cantilever mode in the frequency range from 0.2 Hz to 20 Hz.

    3. Results and discussion

    Figures 2(a1) and 2(a2) exhibit the DSC curves of Ti50Au50-xCrxSMAs. Sharp heat flow peaks are observed during cooling and heating for Cr15 of which the Msis around 385 K,while the heat flow peaks disappear for Cr25. It means that 25 at.% of chromium is enough to suppress the martensitic transformation in Ti–Au SMAs. On the other hand,in Ti50Pt50-yFeySMAs, the doping of 25 at.% iron is still not high enough to lead to the suppression of the martensitic phase. As shown in Fig.2(b1), weak heat flow peaks are detected for Fe25(Ms=403 K),while figure 2(b2)shows that it requires 30 at.%of iron to completely suppress the formation of the martensitic phase.

    Figure 3 exhibits the ER curves with different doping levels for these two systems respectively. Because the martensitic transformation is the first order phase transformation in thermodynamics, it always exhibits a thermal hysteresis loop in the ER curve during cooling and heating. As shown in Fig. 3(a1), a clear thermal hysteresis loop takes place in the ER curve of Cr15, while no hysteresis loop is observed for Cr25 in Fig. 3(a2). It means that the martensitic transformation still exists in Cr15,whereas there is no martensitic transformation in Cr25. A similar case is found in Ti50Pt50-yFeySMAs.The absence of hysteresis loop in the ER curve of Fe30 in Fig.3(b2)indicates that there is no martensitic transformation in Fe30 either.Thus,the ER curves are consistent with the DSC results. Both of them indicate that the martensitic transformations in the two HTSMAs can be completely suppressed by doping excess point defects.

    Fig. 2. DSC curves of Ti50Au50-xCrx and Ti50Pt50-yFey alloys. Heat flow peaks can be observed in(a1)Cr15 and(b1)Fe25, while there is no peak in(a2)Cr25 and(b2)Fe30.

    Fig.3. ER curves of Ti50Au50-xCrx and Ti50Pt50-yFey alloys. Thermal hysteresis loops can be observed in(a1)Cr15 and(b1)Fe25,while the hysteresis loop disappears in(a2)Cr25 and(b2)Fe30.

    It is noted that the strain glass in Ti–Au–Cr alloys exhibits a negative temperature dependence of electrical resistivity in Fig. 3(a2), while the strain glass in Ti–Pt–Fe alloys shows a positive temperature dependence in Fig.3(b2). The electrical resistivity has been well known to be sensitive to the phase structure of the nanodomains in strain glass.[12,14–16]Thus,the difference in the temperature dependence of electrical resistivity suggests that the phase structure of the nanodomains in these two strain glasses is remarkably different,which is worthy to be investigated in the future.

    The storage modulus and tanδ curves of Cr25 and Fe30 are shown in Fig. 4 respectively. In Fig. 4(a), there are two anomalies in the storage modulus curves of Cr25 upon cooling. The first anomaly appears around 300 K, and exhibits a frequency dependent behavior, namely, the dip temperatures in storage modulus decrease with frequency lowering. Corresponding to the dip in storage modulus, the tanδ exhibits a peak,and the peak temperatures show the same frequency dependent behavior. This frequency dependent behavior is a typical glass feature for strain glass as previously reported,which indicates the slowing-down of dynamics during the strain glass transition.[6,7]It thus corresponds to the primary α-relaxation in metallic glass, as shown in Fig. 1(a). The frequency dependence of the dip can be fitted by the Vogel–Fulcher(V–F)relation ω =ω0exp[-Ea/kB(Tg-T0)],[6,7]where ω is the oscillating frequency,ω0the frequency at infinitely high temperature,Eathe activation energy,kBthe Boltzmann constant,Tgthe strain glass transition temperature, and T0the ideal freezing temperature. For convenience, we use the T0to compare the glass transition temperatures of different systems below.According to the V–F relation, the ideal freezing temperature T0is about 251 K.

    Fig. 4. (a) Storage modulus and tanδ curves of Ti50Au25Cr25 (Cr25).Two anomalies are detected in the curves. The anomaly around 290 K exhibits a frequency dependent behavior,corresponds to the strain glass transition. By fitting the V–F relation in the inset of(a),the ideal freezing temperature T0 is around 251 K.The other anomaly around 160 K in the storage modulus curve corresponds to a spontaneous transition from strain glass to martensite. (b) Storage modulus and tanδ curves of Ti50Pt20Fe30 (Fe30). The anomaly around 320 K corresponds to the strain glass transition. According to the V–F relation in the inset of(b),the T0 is around 272 K.Upon cooling,a modulus softening is observed at low temperatures.

    With further cooling, another dip in the storage modulus curves of Cr25 appears around 150 K in Fig.4(a). Meanwhile,the intensity of tanδ increases correspondingly,but the peak cannot be detected. This second anomaly indicates that a spontaneous transition from the strain glass(the frozen local strain ordered state)to martensite(the ferroelastic phase with long-range strain ordering) takes place. Such a spontaneous transition has been widely found in strain glass alloys,[17–19]which suggests that the strain glass is not the ground state of the system at low temperatures.

    The storage modulus and tanδ curves of Fe30 are shown in Fig.4(b). Only one anomaly is clearly found around 320 K,which exhibits the frequency dependent behavior of the dip temperatures in storage modulus and the corresponding peak temperatures in tanδ, the same as the first anomaly of Cr25.By fitting the V–F relation,T0is about 272 K.When the temperature further decreases,no second anomaly can be detected.Despite the absence of the second anomaly,the modulus softening is observed upon cooling below 230 K,which is known as a signal of the onset of the martensitic transition.[18]It suggests that the second anomaly actually exists, but locates at a low temperature below the lower limit of the DMA experiment. As a result, only the strain glass transition is clearly observed for Fe30 by the DMA experiment.

    Fig. 5. Summary of the T0 of current main strain glass alloy systems.The data of Ti–Ni-based strain glasses come from Refs. [6,12,19,20],the data of Ti–Pd-based strain glasses are from Ref.[13], and the data of ferromagnetic strain glass alloys come from Refs.[10,20,21].

    These two new strain glass systems exhibit a relatively high ideal freezing temperature T0, as compared with other systems. Figure 5 summarizes the T0of current main strain glass systems. In Ti–Ni-based strain glass alloys, T0is generally lower than 200 K.[6,12,19,20]Ti–Pd-based strain glass alloys exhibit a relatively high T0, which is around 250 K.[13]As for the ferromagnetic strain glass(FSTG)alloys,the highest T0is also around 250 K.[10,21,22]Thus, the highest T0of current strain glass systems is around 250 K. In comparison,the T0of the Ti50Au25Cr25strain glass alloy is about 251 K,which is comparable with the highest T0value,and that of the Ti50Pt20Fe30strain glass alloy is about 272 K, which is even higher than the T0maximum of the current main strain glass alloys.

    Although the strain glass in the Ti50Pt20Fe30alloy exhibits the highest T0so far,it is not high enough as expected,given that the host alloy Ti50Pt50exhibits a quite high Ms(~1340 K).[2]Figure 6 compares the phase diagrams of several Ti-based alloys.[12,13]The composition dependence of the transformation behavior is similar for these four systems:there is a critical defect concentration separating the martensitic phase and strain glass. It is noted that as the Msof the host alloy increases, the critical defect concentration strongly increases,whereas the increase of the T0is limited. As a result,although the Ti–Pt-based alloys start from the pure Ti50Pt50host alloy with high Ms(~1340 K),much higher than the Msof the pure Ti50Pd50host alloy(~800 K)in Ti–Pd-based alloys,the T0of the strain glass in Ti–Pt-based alloys(~272 K)is only slightly higher than that of the strain glass in Ti–Pdbased alloys(~250 K).

    Fig.6. Comparison of the phase diagrams of Ti-based SMAs. The critical defect concentration for each system is labeled by the red dot line.The data of Ti50Ni50-xFex and Ti50Pd50-xCrx come from Refs.[12,13],and the data of Ti50Pt50 and Ti50Au50 are from Ref.[2].

    Obviously, doping point defects is not an effective way to further increase the T0of strain glass above ambient temperature. According to the phenomenological model of strain glass,[23]point defects generally introduce two effects to the martensitic system: One is a global effect,which changes the global thermodynamic stability of martensite;the other is a local effect,which leads to a fluctuation in local thermodynamic stability of martensite. In most cases,the global effect of point defects is to decrease the Ms,which causes a strong transition temperature decrease before the system goes to the strain glass and thus results in a low T0.

    Besides the point defects,some other crystallographic defects such as dislocations[24]and nanoprecipitates[25,26]have also been reported to be able to suppress the martensitic transformation and generate a frozen strain glass state. Moreover,it is reported that the dislocations and nanoprecipitates can maintain the T0of strain glass better than the point defects.[24]The reason is that the global effect of dislocations is negligible,while nanoprecipitates sometimes may lead to an opposite global effect as compared with point defects(for example,the Msof the B2-R martensitic transition in Ti–Ni SMAs increases due to the Ti3Ni4precipitation[5]). Thus, a potential solution to design high T0strain glass alloys is to choose a host alloy with high Msand introduce other defects such as dislocations and nanoprecipitates in it,which requires a further study in the future.

    Moreover, in ferromagnetic shape memory alloys which are an important subgroup of SMAs,the global effect of point defects may vary due to the magnetoelastic coupling. For example, in Co-doped Ni–Mn–Ga ferromagnetic strain glass alloys, the Msfirst keeps constant rather than decreases with doping cobalt,and the T0in this system is actually comparable with that of strain glass in Ti–Pd-based SMAs.[21]Thus,ferromagnetic shape memory alloys are also a promising candidate to exhibit high T0,worthy to be further investigated.

    4. Conclusion

    We found high temperature strain glass in Ti–Au-based and Ti–Pt-based HTSMAs. The critical defect concentration for Ti50Au50-xCrxalloys is around x = 25, while that for Ti50Pt50-yFeyalloys is about y=30. The T0of strain glass in Ti–Au-based alloys is around 251 K,and that of strain glass in Ti–Pt-based alloys is around 272 K.Both of them are comparable with the highest T0value so far. This work suggests that doping point defects is not an effective way to increase the T0above the ambient temperature,some other methods are required to find the strain glass with higher T0.

    猜你喜歡
    劉暢
    Measurement of International Competitiveness of Clothing Industry under the Background of Value Chain Reconstruction
    水蒸氣變戲法
    春來(lái)啦
    They are just kids
    愛挑剔的番茄
    珍視自我
    劉暢作品
    海參
    夏天咋來(lái)的
    月亮洗澡
    在线观看66精品国产| 美女免费视频网站| 噜噜噜噜噜久久久久久91| 日本一二三区视频观看| 午夜激情福利司机影院| 精品久久久久久久末码| 午夜a级毛片| 国产伦精品一区二区三区视频9 | 久久亚洲真实| 久久久色成人| 非洲黑人性xxxx精品又粗又长| 99在线视频只有这里精品首页| 一级作爱视频免费观看| 可以在线观看的亚洲视频| 热99re8久久精品国产| 亚洲成a人片在线一区二区| 蜜桃亚洲精品一区二区三区| 欧美极品一区二区三区四区| 国内久久婷婷六月综合欲色啪| 99久久成人亚洲精品观看| 九色国产91popny在线| 真实男女啪啪啪动态图| 99久久精品一区二区三区| 国产一级毛片七仙女欲春2| 久久精品国产清高在天天线| 亚洲五月天丁香| 国产69精品久久久久777片| 午夜免费男女啪啪视频观看 | 3wmmmm亚洲av在线观看| 全区人妻精品视频| 午夜影院日韩av| 婷婷六月久久综合丁香| 中文字幕人妻丝袜一区二区| 99精品欧美一区二区三区四区| 精华霜和精华液先用哪个| 亚洲成人中文字幕在线播放| 久久婷婷人人爽人人干人人爱| 精品乱码久久久久久99久播| 色综合站精品国产| 日韩欧美免费精品| 精品久久久久久久末码| 久久久国产成人免费| 操出白浆在线播放| 亚洲精品456在线播放app | 亚洲五月天丁香| 99久国产av精品| 中出人妻视频一区二区| 国产成人aa在线观看| 亚洲在线观看片| 不卡一级毛片| 日韩免费av在线播放| 国产主播在线观看一区二区| 国产高清有码在线观看视频| 婷婷丁香在线五月| 又紧又爽又黄一区二区| 亚洲av成人av| 99热6这里只有精品| 一级毛片高清免费大全| 久久国产乱子伦精品免费另类| 在线观看美女被高潮喷水网站 | 欧洲精品卡2卡3卡4卡5卡区| 久久香蕉精品热| 国产91精品成人一区二区三区| 国模一区二区三区四区视频| 国产色婷婷99| 九九在线视频观看精品| 中文字幕人妻丝袜一区二区| 免费在线观看成人毛片| 网址你懂的国产日韩在线| 欧美av亚洲av综合av国产av| 一区二区三区免费毛片| 怎么达到女性高潮| 人人妻,人人澡人人爽秒播| 淫秽高清视频在线观看| 中文字幕精品亚洲无线码一区| 中文字幕高清在线视频| 国产一区二区在线观看日韩 | 高潮久久久久久久久久久不卡| 动漫黄色视频在线观看| a级毛片a级免费在线| 国内精品久久久久久久电影| 久久久久国产精品人妻aⅴ院| 一a级毛片在线观看| 欧美成人a在线观看| 99久久成人亚洲精品观看| 成人特级黄色片久久久久久久| 精品乱码久久久久久99久播| 一级黄片播放器| 观看免费一级毛片| 又粗又爽又猛毛片免费看| 一个人免费在线观看的高清视频| 99久久综合精品五月天人人| 午夜福利在线观看免费完整高清在 | 成人av一区二区三区在线看| 琪琪午夜伦伦电影理论片6080| 美女 人体艺术 gogo| 91九色精品人成在线观看| 午夜影院日韩av| av视频在线观看入口| 日日干狠狠操夜夜爽| 亚洲精品456在线播放app | 日韩大尺度精品在线看网址| 亚洲专区中文字幕在线| 天天添夜夜摸| 国产精品久久久久久久久免 | 色哟哟哟哟哟哟| 国产国拍精品亚洲av在线观看 | 精品国产亚洲在线| 国产精品一及| 99在线视频只有这里精品首页| 波多野结衣巨乳人妻| 女人高潮潮喷娇喘18禁视频| 亚洲av熟女| 欧美日韩亚洲国产一区二区在线观看| 在线a可以看的网站| 欧美黑人欧美精品刺激| 97超级碰碰碰精品色视频在线观看| 又黄又粗又硬又大视频| 美女高潮喷水抽搐中文字幕| 99久久精品国产亚洲精品| 少妇熟女aⅴ在线视频| 草草在线视频免费看| 男人的好看免费观看在线视频| 国产成人a区在线观看| 在线观看av片永久免费下载| 舔av片在线| 99久国产av精品| 在线a可以看的网站| 一二三四社区在线视频社区8| 一进一出抽搐动态| 亚洲av二区三区四区| 国产精品,欧美在线| 欧美乱妇无乱码| 国产激情偷乱视频一区二区| av欧美777| 男人的好看免费观看在线视频| 中文字幕久久专区| 午夜福利欧美成人| 成人av在线播放网站| 国产精品亚洲美女久久久| 午夜福利欧美成人| 给我免费播放毛片高清在线观看| 熟妇人妻久久中文字幕3abv| 精品乱码久久久久久99久播| 中文字幕精品亚洲无线码一区| 无限看片的www在线观看| 草草在线视频免费看| 亚洲精品影视一区二区三区av| 精品久久久久久久久久免费视频| 国产三级在线视频| 99国产精品一区二区蜜桃av| 亚洲欧美精品综合久久99| aaaaa片日本免费| 99精品久久久久人妻精品| 婷婷丁香在线五月| 成人精品一区二区免费| 好男人电影高清在线观看| 女生性感内裤真人,穿戴方法视频| 成年人黄色毛片网站| 一卡2卡三卡四卡精品乱码亚洲| 老司机深夜福利视频在线观看| 亚洲av五月六月丁香网| 亚洲av成人不卡在线观看播放网| 亚洲av美国av| 午夜精品久久久久久毛片777| 亚洲国产日韩欧美精品在线观看 | 男女床上黄色一级片免费看| h日本视频在线播放| 久久久久久人人人人人| 精品乱码久久久久久99久播| 欧美激情在线99| 在线看三级毛片| 看片在线看免费视频| 国产爱豆传媒在线观看| 久久婷婷人人爽人人干人人爱| 免费观看人在逋| 久久久国产成人免费| www.熟女人妻精品国产| av天堂在线播放| 免费搜索国产男女视频| 看黄色毛片网站| 久久亚洲精品不卡| 夜夜夜夜夜久久久久| 国产老妇女一区| 久久久久久大精品| 国产又黄又爽又无遮挡在线| 91av网一区二区| 青草久久国产| 757午夜福利合集在线观看| 88av欧美| 99久国产av精品| 亚洲一区二区三区色噜噜| 99国产综合亚洲精品| 色尼玛亚洲综合影院| 精品国产亚洲在线| 男女视频在线观看网站免费| 国产午夜精品论理片| 高清日韩中文字幕在线| 免费看日本二区| 日韩中文字幕欧美一区二区| 亚洲欧美日韩卡通动漫| 脱女人内裤的视频| 久久精品国产亚洲av香蕉五月| 女警被强在线播放| 亚洲人成网站在线播放欧美日韩| 69人妻影院| 黑人欧美特级aaaaaa片| 欧美bdsm另类| 在线观看免费午夜福利视频| 欧美不卡视频在线免费观看| 乱人视频在线观看| 99热这里只有是精品50| 国内揄拍国产精品人妻在线| 日本撒尿小便嘘嘘汇集6| 国产视频一区二区在线看| a级毛片a级免费在线| 在线播放国产精品三级| 国产真实伦视频高清在线观看 | 99在线人妻在线中文字幕| 99久久综合精品五月天人人| 国产精品综合久久久久久久免费| 欧美成人一区二区免费高清观看| 内射极品少妇av片p| 深夜精品福利| 精品99又大又爽又粗少妇毛片 | 国内精品美女久久久久久| 性色av乱码一区二区三区2| 午夜精品一区二区三区免费看| 成人三级黄色视频| 午夜激情福利司机影院| 1000部很黄的大片| 桃红色精品国产亚洲av| 国语自产精品视频在线第100页| 亚洲国产欧美人成| 尤物成人国产欧美一区二区三区| 村上凉子中文字幕在线| bbb黄色大片| 亚洲精品一卡2卡三卡4卡5卡| 国产69精品久久久久777片| 亚洲成人免费电影在线观看| 母亲3免费完整高清在线观看| 一区二区三区国产精品乱码| 岛国视频午夜一区免费看| 欧美一级毛片孕妇| 婷婷精品国产亚洲av在线| 日韩高清综合在线| 国产毛片a区久久久久| 欧美黄色片欧美黄色片| 亚洲精品乱码久久久v下载方式 | 真实男女啪啪啪动态图| 99久久精品热视频| 婷婷丁香在线五月| 色在线成人网| 非洲黑人性xxxx精品又粗又长| 亚洲中文字幕日韩| 欧美xxxx黑人xx丫x性爽| 亚洲成av人片在线播放无| 久久中文看片网| 久久精品国产99精品国产亚洲性色| 91久久精品电影网| 亚洲最大成人手机在线| 国产老妇女一区| 国产黄色小视频在线观看| 99热精品在线国产| 99热只有精品国产| 欧美日韩亚洲国产一区二区在线观看| 99国产极品粉嫩在线观看| 中亚洲国语对白在线视频| 搡老熟女国产l中国老女人| 日本精品一区二区三区蜜桃| 精品久久久久久久久久久久久| 最好的美女福利视频网| 亚洲成人久久爱视频| 女同久久另类99精品国产91| 俄罗斯特黄特色一大片| 少妇的逼水好多| 亚洲av免费在线观看| 国产精品久久电影中文字幕| 久久人人精品亚洲av| 操出白浆在线播放| 一区二区三区高清视频在线| 男人的好看免费观看在线视频| 色老头精品视频在线观看| 亚洲av日韩精品久久久久久密| 久久久久久久亚洲中文字幕 | 69人妻影院| 午夜免费男女啪啪视频观看 | 欧美色欧美亚洲另类二区| 在线天堂最新版资源| 日韩欧美免费精品| 免费在线观看日本一区| 免费av毛片视频| 亚洲一区高清亚洲精品| 精品人妻偷拍中文字幕| 亚洲成av人片免费观看| 国语自产精品视频在线第100页| 国产精品爽爽va在线观看网站| 国产在视频线在精品| 在线视频色国产色| 亚洲人成伊人成综合网2020| 悠悠久久av| 母亲3免费完整高清在线观看| 99久久99久久久精品蜜桃| 在线免费观看的www视频| 又爽又黄无遮挡网站| 亚洲 国产 在线| a在线观看视频网站| 日韩国内少妇激情av| 国产精品三级大全| 99久久成人亚洲精品观看| 一级a爱片免费观看的视频| 在线观看免费午夜福利视频| 国产午夜福利久久久久久| 女人十人毛片免费观看3o分钟| 可以在线观看毛片的网站| 一进一出好大好爽视频| 午夜激情欧美在线| 两性午夜刺激爽爽歪歪视频在线观看| 久久国产精品人妻蜜桃| 国产精品一区二区免费欧美| 女同久久另类99精品国产91| 欧美一区二区国产精品久久精品| 国产视频内射| 欧美日韩瑟瑟在线播放| 久久亚洲精品不卡| 欧美日韩乱码在线| 成熟少妇高潮喷水视频| 日本成人三级电影网站| 免费看a级黄色片| 91久久精品国产一区二区成人 | 老司机午夜十八禁免费视频| 午夜免费男女啪啪视频观看 | 小蜜桃在线观看免费完整版高清| 精品人妻1区二区| 少妇裸体淫交视频免费看高清| 老司机午夜福利在线观看视频| www日本在线高清视频| 亚洲美女黄片视频| 欧美成人性av电影在线观看| 女人被狂操c到高潮| 又紧又爽又黄一区二区| 老鸭窝网址在线观看| 欧美乱色亚洲激情| 噜噜噜噜噜久久久久久91| 国产色婷婷99| АⅤ资源中文在线天堂| 国产av一区在线观看免费| 搡老岳熟女国产| bbb黄色大片| 午夜福利在线观看免费完整高清在 | 国产伦一二天堂av在线观看| 亚洲精品色激情综合| 成年免费大片在线观看| 欧美又色又爽又黄视频| 97超级碰碰碰精品色视频在线观看| 男人舔奶头视频| 18禁黄网站禁片午夜丰满| 国产爱豆传媒在线观看| 少妇人妻精品综合一区二区 | 国产免费av片在线观看野外av| 成年女人毛片免费观看观看9| 国产一级毛片七仙女欲春2| 18禁美女被吸乳视频| 亚洲av熟女| 亚洲天堂国产精品一区在线| 大型黄色视频在线免费观看| 观看美女的网站| 国产成人啪精品午夜网站| 亚洲一区二区三区色噜噜| 99国产精品一区二区蜜桃av| 日日夜夜操网爽| 宅男免费午夜| 国产色婷婷99| 欧美性猛交黑人性爽| 人人妻人人看人人澡| 亚洲狠狠婷婷综合久久图片| 久久精品国产亚洲av涩爱 | 色播亚洲综合网| 成年版毛片免费区| 欧美成人一区二区免费高清观看| 久久精品91蜜桃| 日本一二三区视频观看| 一区二区三区高清视频在线| 老司机午夜十八禁免费视频| 亚洲国产精品999在线| 亚洲欧美精品综合久久99| 中文字幕人成人乱码亚洲影| 日本三级黄在线观看| 久久婷婷人人爽人人干人人爱| 国产精品永久免费网站| 18禁国产床啪视频网站| 高潮久久久久久久久久久不卡| 99在线人妻在线中文字幕| 99久久精品一区二区三区| 久久久国产精品麻豆| 国产亚洲精品av在线| 观看美女的网站| 国产精品国产高清国产av| 久久6这里有精品| 9191精品国产免费久久| 无遮挡黄片免费观看| 亚洲国产精品sss在线观看| 欧美成人一区二区免费高清观看| 国产熟女xx| 久久中文看片网| 18禁黄网站禁片午夜丰满| 最新在线观看一区二区三区| 老司机在亚洲福利影院| 久久久久久大精品| 高清在线国产一区| 久久久久亚洲av毛片大全| 亚洲黑人精品在线| 亚洲av中文字字幕乱码综合| 国产精品久久久久久精品电影| 亚洲人与动物交配视频| 午夜两性在线视频| 精品免费久久久久久久清纯| 美女被艹到高潮喷水动态| 国产免费av片在线观看野外av| 精品无人区乱码1区二区| 国产老妇女一区| 制服丝袜大香蕉在线| 免费人成在线观看视频色| 男女做爰动态图高潮gif福利片| 女警被强在线播放| 国产精品久久久久久久电影 | 两个人看的免费小视频| 亚洲av免费在线观看| av专区在线播放| 综合色av麻豆| 久久精品国产亚洲av涩爱 | 中文字幕人妻熟人妻熟丝袜美 | 欧美乱色亚洲激情| 色精品久久人妻99蜜桃| 两个人的视频大全免费| 亚洲成a人片在线一区二区| 欧美在线黄色| 久久国产精品人妻蜜桃| 欧美日韩中文字幕国产精品一区二区三区| 国产精品亚洲美女久久久| 免费人成视频x8x8入口观看| 午夜福利在线观看免费完整高清在 | 午夜福利视频1000在线观看| 老熟妇仑乱视频hdxx| e午夜精品久久久久久久| 搡老岳熟女国产| 欧美中文综合在线视频| 亚洲精品美女久久久久99蜜臀| a级一级毛片免费在线观看| 亚洲avbb在线观看| 日韩免费av在线播放| 精品一区二区三区视频在线 | 欧美日韩瑟瑟在线播放| 午夜老司机福利剧场| 99久久久亚洲精品蜜臀av| 可以在线观看的亚洲视频| 国产高清视频在线播放一区| 99久久精品国产亚洲精品| 日本五十路高清| 欧美一级毛片孕妇| 97超视频在线观看视频| 一区二区三区国产精品乱码| 欧美成人性av电影在线观看| 欧美三级亚洲精品| aaaaa片日本免费| 男人舔女人下体高潮全视频| 午夜精品一区二区三区免费看| or卡值多少钱| 网址你懂的国产日韩在线| tocl精华| 日韩欧美精品v在线| 蜜桃久久精品国产亚洲av| 国产精品免费一区二区三区在线| 看片在线看免费视频| 69人妻影院| 在线a可以看的网站| 成人av在线播放网站| 亚洲成人精品中文字幕电影| 中文字幕人妻熟人妻熟丝袜美 | 免费看光身美女| 99riav亚洲国产免费| 中文字幕av成人在线电影| 国产精品久久久久久久久免 | 90打野战视频偷拍视频| 少妇高潮的动态图| 亚洲av免费高清在线观看| 日韩欧美国产一区二区入口| 欧美极品一区二区三区四区| 一二三四社区在线视频社区8| 搡老熟女国产l中国老女人| 嫩草影院入口| 国产乱人视频| 内地一区二区视频在线| 色综合亚洲欧美另类图片| 丁香六月欧美| 91久久精品国产一区二区成人 | 色精品久久人妻99蜜桃| 亚洲专区中文字幕在线| 欧美极品一区二区三区四区| АⅤ资源中文在线天堂| 亚洲最大成人中文| 国产精品嫩草影院av在线观看 | 搞女人的毛片| 男女之事视频高清在线观看| 久久久久免费精品人妻一区二区| 亚洲国产欧美人成| 国产精品日韩av在线免费观看| 国产又黄又爽又无遮挡在线| 午夜福利欧美成人| 国产精品久久久久久久久免 | 中文字幕久久专区| 中文字幕人妻丝袜一区二区| 国产在线精品亚洲第一网站| 亚洲,欧美精品.| 国产综合懂色| 国产91精品成人一区二区三区| 尤物成人国产欧美一区二区三区| 国产伦精品一区二区三区视频9 | 亚洲精品在线美女| 欧美乱妇无乱码| 12—13女人毛片做爰片一| 在线观看日韩欧美| 国产免费一级a男人的天堂| 一级作爱视频免费观看| 欧美一区二区精品小视频在线| 麻豆成人午夜福利视频| ponron亚洲| 三级毛片av免费| 嫩草影视91久久| 国产中年淑女户外野战色| 国产精品影院久久| x7x7x7水蜜桃| 村上凉子中文字幕在线| 亚洲人成网站高清观看| 一个人免费在线观看电影| 国产极品精品免费视频能看的| 两人在一起打扑克的视频| 免费av毛片视频| 国产亚洲精品综合一区在线观看| 久久精品91无色码中文字幕| 午夜免费成人在线视频| 两个人看的免费小视频| 精品免费久久久久久久清纯| 每晚都被弄得嗷嗷叫到高潮| 精品99又大又爽又粗少妇毛片 | 欧美黑人欧美精品刺激| 亚洲va日本ⅴa欧美va伊人久久| 毛片女人毛片| 啦啦啦免费观看视频1| 天堂网av新在线| 最近最新中文字幕大全免费视频| 久久久久久九九精品二区国产| 午夜福利成人在线免费观看| 国产一区二区亚洲精品在线观看| 亚洲专区国产一区二区| 夜夜夜夜夜久久久久| 国产精品免费一区二区三区在线| 熟妇人妻久久中文字幕3abv| 国产淫片久久久久久久久 | 亚洲精品国产精品久久久不卡| 网址你懂的国产日韩在线| 99热6这里只有精品| 久久精品国产清高在天天线| 熟妇人妻久久中文字幕3abv| 国产淫片久久久久久久久 | 久久久久久国产a免费观看| 波野结衣二区三区在线 | 成人特级黄色片久久久久久久| 好男人在线观看高清免费视频| 国产精品一区二区免费欧美| 小说图片视频综合网站| 99riav亚洲国产免费| 在线a可以看的网站| 欧美黑人巨大hd| 亚洲专区国产一区二区| 最近在线观看免费完整版| 老熟妇仑乱视频hdxx| 别揉我奶头~嗯~啊~动态视频| 在线观看av片永久免费下载| 亚洲一区高清亚洲精品| 2021天堂中文幕一二区在线观| 黄色片一级片一级黄色片| 99视频精品全部免费 在线| www.www免费av| 不卡一级毛片| 女警被强在线播放| 国产野战对白在线观看| 欧美极品一区二区三区四区| 久久精品国产清高在天天线| 天堂网av新在线| 九九热线精品视视频播放| 又黄又粗又硬又大视频| 母亲3免费完整高清在线观看| 在线观看免费视频日本深夜| 免费观看的影片在线观看| 日韩人妻高清精品专区| 三级毛片av免费| 啦啦啦免费观看视频1| 中文字幕人妻熟人妻熟丝袜美 | 国产精品亚洲av一区麻豆| 午夜a级毛片| 国产aⅴ精品一区二区三区波| 国产成人福利小说| 亚洲av中文字字幕乱码综合| 欧美成人性av电影在线观看| 男人舔奶头视频| 久久久精品大字幕| 99国产精品一区二区蜜桃av| 精品人妻1区二区| 国产成人av激情在线播放| 国产精品 国内视频| 亚洲欧美日韩无卡精品| 一级毛片高清免费大全| 给我免费播放毛片高清在线观看| 久久精品夜夜夜夜夜久久蜜豆|