SGER: Development of a Soft Magnetic Material with Enhanced High Temperature Strength

0100621 Putatunda SGER赠款的重点是在高温下具有高蠕变强度的新型超软磁材料。该合金是铁与10-20%的铝，将采用创新的粉末冶金工艺路线，同时热压和烧结。 铁-铝相图表明，铝含量超过10%的铁不会发生奥氏体向铁素体的相变。此外，向铁中添加铝允许在烧结期间显著的晶粒生长。因此，应该可以在具有极低磁导率、非常高的饱和磁感应和非常高的磁导率的超软磁材料中产生大的晶粒尺寸（晶粒直径超过1500 mm）。此外，相图表明，在铝含量为10-20%的铁铝合金中，可能存在Fe 3Al型沉淀物。这些沉淀物应该提供磁畴壁运动的屏障，以及位错运动的障碍，导致在高温下具有高蠕变强度的材料。铁粉和铝粉将按所需比例混合并压实。压实后，将在不同的温度和时间段下烧结绿色产品，以确定完全致密产品的最佳加工条件。该合金的磁性和机械性能将被表征，并与市售的铁硅合金和铁磷合金进行比较。铝对晶粒长大和磁性能的影响将被考虑。通过冷加工和退火以及随后的淬火和时效工艺的明智混合，将在基体中产生Fe 3Al的细小尺度析出物。成功的加工将产生一种新的超软磁材料，具有优异的高温机械性能，成本低，磁性能非常有效，节省能源。%软磁材料是发电设备所需的重要工程材料。这些材料必须具有高磁导率、低磁导率和高饱和磁感应强度。此外，它们必须具有窄的磁滞回线。软磁材料通常在高温下具有差的机械性能。 许多工业应用（例如，高速发电机中的转子、发动机中的磁轴承、辅助动力装置等）需要软磁材料，其不仅可以在高温下保持它们的软磁，而且可以在升高的温度下承受高应力。***

0100621PutatundaThe focus of the SGER grant is on a new, super-soft magnetic material with high creep strength at elevated temperatures. The alloy, iron with 10-20% aluminum, will use an innovative powder metallurgy processing route by simultaneous hot pressing and sintering. The iron-aluminum phase diagram indicates that iron with more than ten percent Al will not undergo the austenite to ferrite phase transformation. Furthermore, the addition of aluminum to iron allows for significant grain growth during sintering. Thus, it should be possible to produce a large grain size (grain diameters in excess of 1500 mm) in a super-soft magnetic material with extremely low coercivity, very high saturated magnetic induction, and very high permeability. Furthermore, the phase diagram indicates that in iron-aluminum alloys with 10-20% aluminum there is a likelihood of Fe3Al-type precipitates. These precipitates should provide barriers to magnetic domain wall movement, as well as obstacles to dislocation movement, resulting in a material with high creep strength at elevated temperatures. Iron and aluminum powders will be mixed in the requisite proportion and compacted. After compaction, the green product will be sintered at different temperatures and time periods to determine optimum processing conditions for a fully dense product. The magnetic and mechanical properties of the alloy will be characterized and compared with commercially available iron-silicon alloys and iron-phosphorus alloys. The influence of aluminum on grain growth and magnetic properties will be considered. Fine scale precipitates of Fe3Al will be produced in the matrix by a judicious mixture of cold working and annealing and subsequent quenching and aging processes. Successful processing will generate a new super soft magnetic material with excellent high temperature mechanical properties at low cost with very efficient magnetic performance and energy savings. %%%Soft magnetic materials are important engineering materials needed in power generation devices. These materials must have high magnetic permeability, low coercivity and high saturated magnetic induction. Moreover, they must have a narrow hysteresis loop. The soft magnetic materials generally have poor mechanical properties at elevated temperatures. Many industrial applications (e.g., rotors in high-speed generators, magnetic bearings in engines, auxiliary power units, etc.) require soft magnetic materials, which not only can retain their soft magnetism at high temperature but also can withstand high stress at elevated temperatures. ***