【作者】 刘燕；

【导师】 王伟民；

【作者基本信息】 山东大学 ， 材料加工工程， 2014， 博士

【摘要】 本文选择由不同冷却速度(Sc)制备的Al86Ni9La5非晶合金作为研究对象,通过对其进行机械加压、压力釜处理、室温低能球磨(LE-BM-RT)、室温高能球磨(HE-BM-RT)和冷冻高能球磨处理(HE-BM-LT),研究了不同的处理方法,对该非晶合金结构、热力学性能、力学性能和耐腐蚀性能的影响。利用X射线衍射仪(XRD)、差示扫描量热仪(DSC)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、振动样品磁强计(VSM)和电化学工作站分析了不同压力下,机械加压对Al86Ni9La5非晶合金的结晶行为、断裂行为、磁学性能和耐腐蚀性能的影响,分析发现：(1) Al86Ni9La5条带在Sc=29.3m/s时经不同压力加压仍保持完全非晶态。然而,在加压过程中,Sc=14.7m/s的条带非晶基体中析出了晶化相。结果表明,加压处理仅影响晶核的长大而不影响生核；(2)加压处理提高了Sc=29.3和14.7m/s时Al86Ni9La5条带的韧性,这与加压处理引入的自由体积和剪切带有关；(3)当Sc=14.7m/s时,随着压力的升高,Al86Ni9La5条带中析出了晶化相,从而加压处理引起腐蚀电位升高然而点蚀电位降低。加压处理降低了Al86Ni9La5条带钝化膜的稳定性,这是由于加压处理使得条带中引入自由体积和剪切带以及析出了晶化相。(4) Al86Ni9La5条带的磁性与其结构有关,预存晶核或晶化相存在的数量越多,Al86Ni9La5条带的顺磁性越强,而非晶相的含量越高,抗磁性越强。利用XRD、DSC、SEM、热膨胀仪(DIL)和显微硬度计分别研究了5MPa机械加压和压力釜处理对Al86Ni9La5条带的微观结构、热力学性能、显微硬度及表面形貌的影响。分析结果发现：(1)原带的第二晶化开始温度Tx2和收缩度6有随着Sc增加而增加的趋势,与此相反,原带的预峰高度,显微硬度压痕附近的变形区尺寸l和剪切带间距有随着Sc增加递减的趋势。这些结果可以归因于在较高的Sc时原带中骨架原子团的数量比较多。骨架原子团可以被5MPa机械加压和压力釜处理稳定化；(2)在Sc=14.7m/s时,经5MPa机械加压和压力釜处理后,Al86Ni9La5条带中都析出富AI相,然而在Sc=22.0和29.3m/s时却没有析出。在原带和处理后的条带中,随着Sc由14.7增加到29.3m/s,压痕的周围产生半圆形的Ⅰ型剪切带的条数从3或4个变为了2个。将这些现象与原带中随Sc增加、α值的非线性降低相结合,可以解释为当Sc达到某一临界值后骨架原子团发生了逾渗。分别通过采用不同试验参数的室温低能球磨、室温高能球磨和冷冻高能球磨对Al86Ni9La5条带进行了处理,并对试样进行了XRD、DSC、SEM和电化学测试,发现：(1)与室温球磨相比,Al86Ni9La5非晶合金在冷冻球磨条件下表现出更强的脆性,经21min的冷冻高能球磨后Al86Ni9La5非晶合金粒度可达微米级；(2)经不同的球磨处理后Al86Ni9La5非晶合金在结构上产生了明显的差别：经30和60min的室温低能球磨后,Al86Ni9La5非晶合金的结构发生了无序化的回复,但室温低能球磨时间增大到120min时,Al86Ni9La5非晶合金的结构又向有序化转变；而高能球磨使得Al86Ni9La5非晶合金中的骨架原子团明显失稳,并且由较低的Sc制备的Al86Ni9La5非晶合金在高能球磨后发生了晶化,较高的Sc制备的Al86Ni9La5非晶合金结构变得有序。而且低温能进一步促进晶化。(3)经室温低能球磨和冷冻高能球磨后,Al86Ni9La5非晶合金的腐蚀电位均有所提高,但钝化区间的宽度明显降低,尤其是冷冻高能球磨,使得Al86Ni9La5非晶合金的钝化区间大为降低。Al86Ni9La5非晶合金钝化区的宽度与非晶基体中的骨架原子团有关,骨架原子团数量越多,钝化区的宽度越宽或钝化膜的稳定性越高。更多还原

【Abstract】 In the present thesis, Al86Ni9La5amorphous alloy spun with different cooling rates was chosen as the study object. Through mechanical compression, autoclave treatment, low energy ball-milled at room temperature (LE-BM-RT), high energy ball-milled at room temperature (HE-BM-RT) and high energy ball-milled at cryogenic temperature (HE-BM-LT), the effects of different treatment conditions on the amorphous structure, thermodynamic properties, mechanical properties and corrosion resistance were studied.The effects of compression on crystallization behavior, fracture behavior and corrosion resistance of Al86Ni9La5ribbons has been studied by using X-ray diffraction (XRD), differential scanning calorimeter (DSC), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM) and electrochemistry station. The results reveal that:(1) The Al86Ni9La5ribbons spun with Sc=29.3m/s keep fully amorphous under different pressures. However, the ribbons spun with Sc=14.7m/s precipitate crystalline phases in amorphous matrix during the compression. The results indicate that the compression only affects the growth of nuclei instead of nucleation;(2) Compression improves the toughness of the Al86Ni9La5ribbons spun with Sc=29.3and14.7m/s, which is associated with the free volume and shear bands induced by compression;(3) The passive film stability of Al86Ni9La5ribbons is weakened by compression, which induces the free volume and shear bands and the precipitation of crystalline phases into the ribbons. With Sc=14.7m/s, the corrosion potential increases while pitting potential decreases with increasing compression pressure due to the precipitation of crystalline phases;(4) The magnetism of Al86Ni9La5ribbons are related with their structure. The more quenched-in nuclei or crystalline phases exist in the ribbons, the stronger is the paramagetism. While, the higher the content of the amorphous phase, the stronger the diamagnetism is.The Al86Ni9La5ribbons are spun with different circumferential speeds Sc and treated with5MPa compression and autoclave conditions. The thermal properties, microhardness and surface morphology of ribbons have been investigated. From these experimental results, the major conclusions are summarized as the following:(1) The onset temperature Tx2of second crystallization and the contraction degree δ of as-spun ribbons have an increasing tendency with increasing Sc.In contrast, the pre-peak height, deformed zone size l and inter-shear-band spacing near the microhardness indentations of the as-spun ribbons have a decreasing tendency with increasing Sc. These results can be ascribed to the argument that the amount of backbone clusters in the as-spun ribbons is larger at a higher Sc. The backbone clusters can be stabilized by5MPa compression and autoclave treatment;(2) In case of both5MPa compression and autoclave treatment, Al-rich phases precipitate in the ribbons with Sc=14.7m/s, but are absent in the ribbons with Sc=22.0and29.3m/s. In as-spun and treated ribbons, the number of edges of the indentation, from which semi-circular shear bands I emanate, varies from3or4to2when the Sc increases from14.7to29.3m/s. Both phenomena together with the non-linear decrease of a for the as-spun ribbon with increasing Sc can be explained by percolating backbone clusters when Sc reaches a critical value.The Al86Ni9La5ribbons which are treated with low energy ball-milling at room temperature, high energy ball-milling at room temperature and high energy ball-milling at cryogenic temperature at different milling time are studied by XRD, DSC, SEM and electrochemical experiment. It is found that:(1) Compared with low energy ball-milling at room temperature, the Al86Ni9La5ribbons showed higher brittleness after highe energy ball-milled at cryogenic temperature. And the Al86Ni9La5ribbons are grinded into particals with the size of about several micrometers.(2) After different types of ball-milling, the milled Al86Ni9La5ribbons occurs obvious difference:after30and60minutes low energy ball-milling at room temperature, the structure of the Al86Ni9La5ribbons occurs disorder rejuvenation; while, when the milling time increases to120minutes, the structure occurs order transformation. However, the amorphous structure of the Al86Ni9La5ribbons is destroyed after high energy ball-milled. Even the ribbons quenched with the relatively low Sc occured distinct crystallization. And the structure of the ribbons quenched with higher Sc occur order transformation.(3) After both the low energy ball-milling at room temperature and high energy ball-milling at cryogenic temperature, the corrosion potentials of the Al86Ni9La5ribbons increase and the width of passive zones decrease. Especially, the high energy ball-milling at cryogenic temperature led to the obvious shorten of the passive zones. The width of passive zone of Al86Ni9La5alloy is related with the quantity of backbone clusters in the amorphous matrix. The more backbone clusters exist, the larger width is passive zone.更多还原