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为发展一种可用于燃气轮机的新型耐热合金,用机械合金化及热挤压工艺方法制备了以Fe-25Cr-6Al 和Fe-25Cr-11Al 为基体成分的合金。研究了不同弥散相Y_2O_3和Al_2O_3含量对于生成长晶粒组织的难易程度以及1100℃机械性能的影响。加入铪虽易使其产生长晶拉,提高合金强度,但只是部分有效。钨的加入阻碍了长晶粒的形成,并且合金的可锻性不如无钨的合金。但含钨合金的高温抗拉性能提高。钇的加入(代替Y_2O_3)减少了Al_2O_3的生成并且改善了反应生成长晶粒所必须的可锻性。所以试验合金必须既包含有Y_2O_3的基本弥散相,同时能再结晶成长晶粒组织。用上述试验结果制备以Fe-25Cr-11Al 为基体成分并含钨和钇的合金,这种合金与国际镍公司商品牌号MA956合金相比,具有较高的高温抗拉强度,但没有改善它们的长时持久强度。
In order to develop a new type of heat-resisting alloy for gas turbine, an alloy containing Fe-25Cr-6Al and Fe-25Cr-11Al as matrix components was prepared by mechanical alloying and hot-extrusion process. The effects of different dispersions Y_2O_3 and Al_2O_3 on the ease of growth of long grain and the mechanical properties at 1100 ℃ were investigated. Although adding hafnium easy to make it produce long crystal pull, improve the strength of the alloy, but only partially effective. The addition of tungsten hinders the formation of long grains and the alloy is not as malleable as the tungsten-free alloy. However, high-temperature tensile properties of tungsten-containing alloys improve. The addition of yttrium (instead of Y_2O_3) reduced the formation of Al_2O_3 and improved the formability necessary for the reaction to produce long grains. Therefore, the test alloy must contain both the Y_2O_3 basic dispersion phase, while recrystallization growth of the grain structure. Using the above test results, an alloy containing Fe-25Cr-11Al as a matrix component and containing tungsten and yttrium was prepared. This alloy has high high-temperature tensile strength but does not improve their tensile strength compared with that of international nickel company MA956 alloy Long-lasting strength.