摘要
研究了二次热处理对成品超因瓦合金的磁性能与热膨胀特性的影响.在900～1 100 ℃的温度范围内进行二次热处理,优化了合金的微观组织结构.XRD表征结果显示,合金在热处理前后均具有fcc相结构,并无新的相生成,但晶面取向更加明显.EBSD表征结果显示,二次热处理后,合金晶粒显著增大,位错孪晶数量明显减少,晶粒均匀性有所改善.MFM表征结果显示,二次热处理后,合金磁畴尺寸增大,强度降低,细小畴发生宽化合并,畴壁数量减少.磁性能和热膨胀系数测试结果显示,随着二次热处理温度的升高,合金的磁性能明显改善,同时,热膨胀系数(CTE)也明显增大.然而,研究发现T1050样品表现出高磁性能低CTE特性,通过测量分析-20～120 ℃下样品B2,500-T曲线,发现T1050样品B2,500随温度升高的衰减大于其他样品,这可能是其具有高磁性能低CET特性的一个原因.
Abstract
Influence of secondary heat treatment on the magnetic properties and thermal expansion characteristics of finished Super-Invar alloy were investigated.By conducting the secondary heat treatment within the temperature range of 900-1 100 ℃,the microstructure of the alloy was optimized.XRD characterization results indicated that the alloy maintained the fcc phase structure before and after heat treatment,with no new phase generated,but more dis-tinct crystal orientation.EBSD characterization results revealed significant grain growth,reduced twinning density,and improved grain uniformity after the secondary heat treatment.MFM characterization results showed that the magnetic domain size increased,while the intensity decreased.Fine domains underwent broadening and merging,and the number of domain walls decreased after the secondary heat treatment.The testing results of magnetic prop-erties and coefficient of thermal expansion demonstrated that,as the temperature of the secondary heat treatment in-creased,the magnetic properties of the alloy improved significantly,accompanied by a noticeable increase in the co-efficient of thermal expansion(CTE).However,it was observed that the T1050 sample exhibited high magnetic performance but low CTE.By measuring and analyzing the B2,500-T curve of the sample at-20 to 120 ℃,it was found that the decay of B2,500 with increasing temperature of the T1050 sample was greater than other samples,which might be a reason for its high magnetic properties and low CTE characteristics.
NETL
NSTL
万方数据