使用真空电弧炉熔炼了不同成分的Al-Er-B合金,将合金放入石英玻璃管中抽真空后,在773 K的温度下保温720 h,然后使用冰水进行水淬。运用X射线衍射、金相分析等方法对退火720 h的合金试样进行了研究。测定了Al-Er-B三元相图773 K等温截面。实验结果表明,该等温截面包含以下3个三相区:第一个三相区为AlEr、Al 2Er 3、ErB 2,第二个三相区为Al 3Er、Al 2Er、ErB 4,第三个三相区为Al、Al 3Er、ErB 4。 Al-Er-B alloys with different compositions were melted using a vacuum arc fur-nace. The alloy was placed in a quartz glass tube for vacuum extraction and kept at a temperature of 773 K for 720 hours. Then, it was quenched with ice water. The alloy samples annealed for 720 h were studied by means of X-ray diffraction and metallographic analysis. The isothermal cross-section of the Al-Er-B ternary phase diagram at 773 K was determined. The experimental results show that the isothermal crosssection consists of three three-phase regions: the first three-phase region is AlEr, Al 2Er 3, and ErB 2, the second three-phase region is Al 3Er, Al 2Er, and ErB 4, and the third three-phase region is Al, Al 3Er and ErB 4.
使用真空电弧炉熔炼了不同成分的Al-Er-B合金,将合金放入石英玻璃管中抽真空后,在773 K的温度下保温720 h,然后使用冰水进行水淬。运用X射线衍射、金相分析等方法对退火720 h的合金试样进行了研究。测定了Al-Er-B三元相图773 K等温截面。实验结果表明,该等温截面包含以下3个三相区:第一个三相区为AlEr、Al2Er3、ErB2,第二个三相区为Al3Er、Al2Er、ErB4,第三个三相区为Al、Al3Er、ErB4。
铝合金,稀土,三元相图,等温截面
Zhengji Lao1, Jiecheng Yang1, Wentian Luo1, Zhaodong Xiong1, Guoqiang Lin1,2*
1College of Resources, Environment and Materials, Guangxi University, Nanning Guangxi
2Key Laboratory of High Performance Structural Materials and Thermo-Surface Processing (Guangxi University), Education Department of Guangxi Zhuang Autonomous Region, Nanning Guangxi
Received: Apr. 13th, 2023; accepted: Jun. 18th, 2023; published: Jun. 25th, 2023
Al-Er-B alloys with different compositions were melted using a vacuum arc furnace. The alloy was placed in a quartz glass tube for vacuum extraction and kept at a temperature of 773 K for 720 hours. Then, it was quenched with ice water. The alloy samples annealed for 720 h were studied by means of X-ray diffraction and metallographic analysis. The isothermal cross-section of the Al-Er-B ternary phase diagram at 773 K was determined. The experimental results show that the isothermal cross-section consists of three three-phase regions: the first three-phase region is AlEr, Al2Er3, and ErB2, the second three-phase region is Al3Er, Al2Er, and ErB4, and the third three-phase region is Al, Al3Er and ErB4.
Keywords:Aluminum Alloy, Rare Earth, Ternary Phase Diagram, Isothermal Cross-Section
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铝合金具有密度低、比强度高、耐腐蚀性好、有极高的可回收性等优点,广泛应用于汽车、航空航天等领域 [
通过添加细化剂达到细晶强化的铝合金强化方法被广泛应用到实际生产中。晶粒细化是获得优良铝合金的重要手段之一,也是最简单最有效的方法。在众多的细化剂中,Al-Ti-B中间合金是使用最广泛且细化效果较好的细化剂之一 [
在铝钛硼中间合金中加入稀土,可以改善其细化作用 [
本文通过实验研究了Al-Er-B三元系在773 K的相平衡关系。运用金相分析(OM),X射线衍射物相分析(XRD)等方法对退火720 h的合金试样进行了研究。测定了Al-Er-B三元系相图773 K等温截面。
实验原料为铝硼合金(AlB8纯度 ≥ 99.3%)和稀土铒(Er纯度 ≥ 99.9%),Al-Er-B合金样品的化学成分(原子百分比)如表1所示。样品成分的选定方法为三元相图常用的布点方法,即在不同三相区的中心附近布点,然后通过三元相图读取出Al、Er、B的百分含量。
对实验材料进行裁剪、清洗、干燥、称量。将样品在真空电弧炉下电弧熔炼成大小均匀的扁球形合金块,再对合金块进行石英玻璃管抽真空密封保存,后将样品放入保温炉内在500℃下保温720 h,保温结束后立即在冰水下水淬。
后续进行样品研磨、使用X射线衍射仪进行XRD衍射实验,对实验样品进行物相分析,XRD实验使用的是Cu靶,电压40 kV,电流150 mA,扫描角度10˚~70˚,扫描速度:6˚/min,(DS = 1˚, DHLS = 1.2 mm, SS = 1˚, RS = 0.3 mm)。
电弧熔炼使用的设备为北京物科光电技术有限公司的WK系列真空电弧炉,X射线衍射(XRD)使用的设备为日本理学Rigaku D/MAX 2500 V型X射线衍射仪。
序号 | Al | Er | B | 熔炼前质量(g) | 熔炼后质量(g) |
---|---|---|---|---|---|
1 | 15.2% | 81.5% | 3.3% | 2.9988 | 2.9981 |
2 | 34.5% | 58.0% | 7.5% | 2.9939 | 2.9890 |
3 | 41.5% | 49.5% | 9.0% | 2.9906 | 2.9291 |
4 | 51.8% | 37.0% | 11.2% | 3.0040 | 2.9697 |
5 | 62.0% | 24.5% | 13.5% | 2.9910 | 2.9138 |
6 | 73.1% | 11.0% | 15.9% | 3.0048 | 2.9814 |
表1. Al-Er-B合金化学成分(原子百分比)
通过对Al、Er、B三种元素的定量制备,然后利用X射线衍射对样品进行物相分析,可以得到Al-Er-B三元相图在500℃的等温截面的一部分,见图1。本文设计的6个样品的成分见表1,分布点位置见图1,通过对1至6号样品进行X射线衍射分析,从衍射结果中可以得出:3号样品的组成相是:AlEr (17-0669, PDF(粉末衍射数据库)编号,下同),Al2Er3 (17-0668),ErB2 (24-1076);5号样品的组成相是:Al3Er (65-6131),Al2Er (65-7085),ErB4 (24-1077);6号样品的组成相是:Al3Er (65-6109),Al (89-4037),ErB4 (65-2264)。
由以上X射线衍射结果,可知图1中,Al-Er之间存在Al2Er3、AlEr、Al2Er、Al3Er四种化合物;Er-B之间存在ErB2、ErB4两种化合物;未发现Al、B之间形成的二元化合物。且存在Al2Er3-AlEr-ErB2、Al2Er-Al3Er-ErB4和Al3Er-Al-ErB4这3个三相区。
图1. Al-Er-B三元相图500℃等温截面(部分)
分别对1号至6号样品进行X射线衍射分析。3号样品Al41.5Er49.5B9的X射线衍射图谱如图2所示,各物相的最强峰之中,最高峰为AlEr,最低峰为ErB2,结合图1中3号样品的布点位置分析可知,可能是因为其成分位置离ErB2较远而导致样品中的ErB2含量较低。分析表明3号样品由AlEr、Al2Er3以及ErB2三相组成。
图2. 3号样品X射线衍射图谱
如图3所示,在5号样品Al62Er24.5B13.5的X射线衍射图谱中,各物相的最强峰之中,最高峰为Al3Er,第二高峰为Al2Er,最低峰为ErB4,且其峰值高度与前两者相差较大,同样结合图1分析可知5号样品中ErB4的含量较低。分析表明5号样品由Al3Er、Al2Er以及ErB4三相组成。
如图4所示,6号样品Al73.1Er11B15.9的X射线衍射图谱中,最强峰为Al。分析表明6号样品由Al、Al3Er、ErB4三相组成。
图5、图6是3号样品Al41.5Er49.5B9在光学显微镜下的金相图,从颜色方面来看存在三种颜色的相,从形状方面来看则存在四种组织,分别为白色的基体,灰色分布不均的晶粒,黑色网状条纹以及分布不均的黑点。结合3号样品的X射线衍射结果对金相图进行分析,大致可以猜测黑色网状条纹和黑点可能为同一个相,可能因为共晶、析出等原因从而表现出两种不同的形态。
图3. 5号样品X射线衍射图谱
图4. 6号样品X射线衍射图谱
图5. 3号样品100倍金相图
图6. 3号样品500倍金相图
在Al-Er-B三元系合金773 K的等温截面中,包含有3个三相区,分别是:3号样品的三相区组成相为AlEr、Al2Er3、ErB2,5号样品的三相区组成相为Al3Er、Al2Er、ErB4,6号样品的三相区组成相为Al、Al3Er、ErB4。
实验结果为稀土Er在铝合金中的应用提供了有价值的实验数据参考,这将有助于未来的研究和开发。
本论文得到了广西大学大学生创新创业项目(项目编号:202110593348)的支持。
本论文得到了基金项目:国家自然科学基金区域创新发展联合基金重点项目(U20A20276)的支持。
劳政基,杨杰城,罗文添,熊昭栋,林郭强. Al-Er-B三元相图773 K等温截面的实验测定 Experimental Determination of 773 K Isothermal Cross Section of Al-Er-B Ternary Phase Diagram[J]. 材料科学, 2023, 13(06): 529-535. https://doi.org/10.12677/MS.2023.136056
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