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一前言燃气涡轮发动机的高温材科,现在可以说到了单晶合金时代。单晶合金目前已在军用或民用航空发动机上实用化了,工业用或船用燃气轮机使用该种合金也已为期不远。单晶合金与以往的合金相比没有晶粒边界,不需要添加用于提高晶粒边界强度的碳或碳化物以及用于改良延展性的硼或铪,因此,可以提高镍基合金的熔点。在晶粒边界中添加异种元素和不添加异种元素时的Mar-M200耐热合金的熔点差异如图1所示。图中左侧添加铪(Hf)的DS(定向凝固)的Mar-M200合金的熔点为1204℃(2200°F),而右侧在晶粒边界中不含
A foreword Gas turbine engine high temperature materials, can now come to the single crystal alloy era. Monocrystalline alloys are currently in commercial use on military or civil aircraft engines, and the use of such alloys for industrial or marine gas turbines is also not far off. The single crystal alloy has no grain boundary compared with the conventional alloy, does not require the addition of carbon or carbide for improving the grain boundary strength, and boron or hafnium for improving the ductility. Therefore, the melting point of the nickel-based alloy can be increased. The melting point difference of Mar-M200 heat-resistant alloy with addition of different elements and no addition of different elements in the grain boundaries is shown in FIG. 1. The Mar-M200 alloy with DS (directional solidification) added hafnium (Hf) on the left side of the figure has a melting point of 1204 ° C (2200 ° F) and the right side contains no