ZrTiAlV合金的力学行为研究

IMR OpenIR

	ZrTiAlV合金的力学行为研究
	王杰
学位类型	硕士
导师	张海峰
	2012
学位授予单位	中国科学院金属研究所
学位授予地点	北京
学位专业	材料学
关键词	新型zr-ti合金应变速率温度动态压缩 New Zr-ti Alloy Strain Rate Temperature Dynamic Compress
摘要	"Zr-Ti-Al-V系合金在常温下能表现出优异的力学性能，特别是在当Zr和Ti的含量（重量百分比）约为1:1时其性能最佳。为探究该系合金在空间中的高、低温、空间碎片撞击等环境下的力学行为，从而为其应用于空间环境提供数据参考，本文针对47Zr-45Ti-5Al-3V合金（重量比），在-100℃、20℃、100℃、200℃温度和不同应变速率条件下，对其准静态拉伸、准静态压缩及动态压缩力学性能进行了研究。研究发现，该合金为双相结构，基体为bcc结构的β相，并在其中均匀分布大量板条状组织、hcp结构的α相。用INSTRON 5582电子万能材料试验机进行了不同温度下、不同应变速率的准静态拉伸和压缩试验。合金在拉伸时和压缩时均表现出极高的屈服强度和断裂强度，拉伸时为脆性断裂，延伸率不足4%，压缩时为塑性断裂，压缩应变都超过了10%。在不同的温度和应变速率下拉伸时，合金在-100℃、10-2s-1时有最高的强度，其屈服强度为1595MPa，抗拉强度为1614MPa，同时延伸率最小，为1.6%；在200℃、10-4s-1时有最低的强度，其屈服强度为1201MPa，抗拉强度为1283MPa，同时延伸率最大，为3.9%。在不同的温度和应变速率下压缩时，合金在-100℃、10-2s-1时有最高的强度，其屈服强度为1421MPa，断裂强度为1953MPa，同时压缩应变最小，为10.9%；在200℃、10-4s-1时有最低的强度，其屈服强度为955MPa，断裂强度为1237MPa，同时压缩应变最大，为15.6%。当温度一定时，随着应变速率的增加，合金的屈服强度和抗拉强度都逐渐增加，同时其应变逐渐减小；当应变速率一定时，随着温度的升高，合金的屈服强度和断裂强度都逐渐减小，同时其应变逐渐增加。但应变速率变化时强度变化很小，而温度变化时强度变化相当明显，可见准静态条件下温度对合金力学性能的影响比应变速率要大得多。用分离式霍普金森压杆进行了不同温度下、不同应变速率的动态压缩试验。动态压缩时合金的屈服强度比准静态时要高，但却没有加工硬化现象出现。合金在-100℃、5000s-1时有最高的屈服强度，为2164MPa，在200℃、1500s-1时有最低的屈服强度，为1317MPa。在室温，高温及-50℃、1500s-1时合金表现出较高的压缩应变，达10%～20%，但在其它低温条件下试样压缩应变明显降低，只有5%左右。当温度一定时，随着应变速率的增加，合金的屈服强度逐渐增加，其增幅在300MPa左右，另外当试样破坏情况相同时，合金的压缩应变逐渐降低；当应变速率一定时，随着温度的升高，合金的屈服强度和抗拉强度都逐渐减小，其降幅在400MPa～500MPa，另外当试样破坏情况相同时，合金的压缩应变逐渐增加。在动态压缩时，应变速率和温度对合金屈服强度的影响非常接近。用Johnson-Cook本构模型对实验结果进行了拟合，得出了动态条件下的本构模型。对比实验结果和拟合结果可以发现，两种结果在高温下吻合较好，随着温度的逐渐降低，逐渐出现越来越大的误差。"
其他摘要	"The alloys of Zr-Ti-Al-V system have very good mechanical properties at room temperature, especially the best when the mass of Zr nears that of Ti. In order to investigate the mechanical behavior of this alloy system in the space environment like high temperature, low temperature, and impact of the space pieces, so as to support a database for its space application, a test about 47Zr-45Ti-5Al-3V(wt.%) alloy has been carried out. This test involves quasi-static tensile, compress and dynamic compress in different strain rates at temperatures of -100℃, 20℃, 100℃ and 200℃. The main contents and results are as follows. The results of metallurgy and TEM show that the alloy contains two phases, in which the β phase with bcc structure is the base, and the plate-shaped α phase with hcp structure is dispersed evenly in the alloy. With the INSTRON 5582 material test machine, quasi-static tensile and compressive tests of different temperatures, different strain rates are carried out. This alloy has quite high yield strength and fracture strength in tensile and compressive tests. When it fractures in tensile test, it is brittle, with the elongation less than 4%. When it fractures in compressive test, it is ductile, with the compressive strain more than 10%. In the tensile test results in different conditions, we have the highest strength with the temperature -100℃ and the strain rate 10-2s-1, and the least elongation of 1.6%. The yield strength is 1595MPa, and the fracture strength is 1614MPa. We have the lowest strength with the temperature 200℃ and the strain rate 10-4s-1, and the most elongation of 3.9%. The yield strength is 1201MPa, and the fracture strength is 1283MPa. In the compressive test results in different conditions, we have the highest strength with the temperature -100℃ and the strain rate 10-2s-1, and the least compressive strain of 10.9%. The yield strength is 1421MPa, and the fracture strength is 1953MPa. We have the lowest strength with the temperature 200℃ and the strain rate 10-4s-1, and the most compressive strain of 15.6%. The yield strength is 955MPa, and the fracture strength is 1238MPa. With the temperature the same, the strength arises and the strain falls as the strain rate arises. With the strain rate the same, the strength falls and the strain arises as the temperature arises. But the strength change as strain rate changes is very little, while very much as temperature changes, so we know that in quasi-static conditions, the temperature gives more obvious influence to the alloy’s mechanical properties than the strain rate does. With the Split Hopkinson Pressure Bar (SHPB), we carried out dynamic compressive tests in different temperatures and different strain rates. We have higher yield strength in dynamic compress than in quasi-static conditions, but no work hardening. We have the highest yield strength of 2164MPa with the temperature -100℃ and the strain rate 5000s-1, and the lowest strength of 1317MPa with the temperature 200℃ and the strain rate 1500s-1. The alloy has a compressive strain as much as 10%～20% with the room temperature, high temperature, and the condition of -50℃、1500s-1, but the strain falls to as less as 5% quickly in the other low temperature conditions. In the comparison of testing results and fitting results, we can know that the results fit well at room temperature and high temperatures, but varies larger and larger as the temperature becomes low."
文献类型	学位论文
条目标识符	http://ir.imr.ac.cn/handle/321006/64536
专题	中国科学院金属研究所
推荐引用方式 GB/T 7714	王杰. ZrTiAlV合金的力学行为研究[D]. 北京. 中国科学院金属研究所,2012.