High Temperature Strength of Al-Fe-(Cr, Mn, V)-Ti Alloys with Dispersed Quasi-Crystalline Particles Solidified by Powder Metallurgy

内容摘要：高温强度铝基合金的合金设计原则是：组成元素的原子尺寸应相差较大；合金应是多组分的；主组分元素之间的混合热应为负；添加元素应具有较低的扩散系数。结果表明，液体淬火的Al-Fe-Cr-Ti-Co-Mo合金体系具有一定的成分范围，准晶的细小颗粒分散在fcc-Al相中。在挤压温度= 673 K，挤压比= 11的条件下，采用PM对上述成分（Al含量为93 ~ 95 at%）的快速淬火合金粉末进行凝固。制备的PM合金在573 K和673 K时的抗拉强度（σuts）分别为>300 MPa和>150 MPa。透射电镜（TEM）分析表明，fcc al相中分散有尺寸约为100 nm、具有高温稳定性和高硬度的准晶。高温强度归因于TEM观察到的结构。其中，Al_<93>Fe_<2.45>Cr_<2.45>Ti_<0.8>Co_<0.8>Mo_<0.5>合金在573 K和673 K时的强度分别为364 MPa和203 MPa。意义=铝合金在573 K时的高温强度目标值为bb0 ~ 300 MPa。本研究开发的Al_<93>Fe_<2.45>Cr_<2.45>Ti_<0.8>Co_<0.8>Mo_<0.5>合金PM材料的高温强度远高于上述数值，达到了目的。重要性：本研究开发的铝合金重量轻，高温强度高，可用于运输机械的高温部件，以寻求燃料成本的提高。因此，开发的铝合金作为解决环境问题的候选材料之一是非常重要的。

Abstract of contents: Alloy design policies of Al-base alloys with high temperature strength was as follows: 1) Atomic sizes of composition elements should be widely different, 2) Alloys should be multi-components, 3) Heat of mixing among main component elements should be negative and 4) Added elements should have lower diffusion coefficient. As a result, we found that a liquid quenched Al-Fe-Cr-Ti-Co-Mo alloy system have a certain composition range where the fine particles of quasi-crystals are dispersed in fcc-Al phase.Rapidly quenched alloy powder of the above composition (content of Al was 93-95 at%) was solidified by PM under conditions of extrusion temperature = 673 K and extrusion ratio = 11. The high temperature strength of thus prepared PM alloy was excellent showing the tensile strength (σuts) of >300 MPa and >150 MPa at 573 K and 673 K, respectively. Transmission electron microscopy (TEM) showed that quasi-crystallites of about 100 nm in size with high temperature stability and high hardness were dispersed in the fcc Al-phase. The high temperature strength was attributed to the structure observed by TEM. Especially, ours of Al_<93>Fe_<2.45>Cr_<2.45>Ti_<0.8>Co_<0.8>Mo_<0.5> alloy was very high, that is, 364 MPa and 203 MPa at 573 K and 673 K, respectively.Significance= The target figure of the high temperature strengh of Al-alloy was >300 MPa at 573 K. The high temperature strengh of Al_<93>Fe_<2.45>Cr_<2.45>Ti_<0.8>Co_<0.8>Mo_<0.5> alloy PM material developed by present research is much higher the figure, and therefore, we attained the purpose.Importance: This developed Al-alloys having light-weight and high temperature strength can be used for the high temperature part of the transportation machines to seek the fuel cost improvement. And therefore, this developed Al-alloys are very important materials as one of candidate for the environmental problems solution.