Fe-12Cr-2Al-3Mo合金减振性能的研究

从具体工程应用出发,研究了Fe-12Cr-2Al-3Mo合金的阻尼性能。采用倒扭摆测试仪测试合金丝材的内耗值,用振动测试仪测试合金圆桶构件的减振性能。结果表明,Fe-12Cr-2Al-3Mo合金内耗值明显高于0Cr18Ni9Ti不锈钢;圆桶构件的振动加速度峰值为0Cr18Ni9Ti不锈钢的1/5。利用磁畴结构可以解释Fe-12Cr-2Al-3Mo合金具有高减振性能的原因。

Study on Thermomagnetic Treatment Fe-25.5Cr-12Co Permanent Magnetic Alloy

The magnetic properties and microstructure in a low cobalt Fe-25.5Cr-12Co alloy by different process of thermomagnetic treatment were investigated. It is found that magnetic properties are sensitive to parameters of thermo- magnetic treatment process in magnetic field, including temperature, time and applied magnetic field. There are optimized isothermal aging temperature and time in different magnetic heat treatment conditions. High magnetic field strength could improve magnetic properties. Applied magnetic field has a great effect on microstructure of the Fe-25.5Cr-12Co alloy. The finer ferromagnetic d] particles with suitable c/a ratio by high magnetic field magnetic heat treatment are attributed to improvement the magnetic properties.

铝含量对Fe-12Cr-1.5B-Al合金凝固组织和硬度的影响

用真空感应炉熔炼含0-8.0%Al的Fe-12Cr-1.5B-Al合金。采用光学显微镜、扫描电镜、XRD、洛氏、维氏硬度计,研究了铝含量对Fe-12Cr-1.5B-Al合金凝固组织和硬度的变化规律。结果表明:无铝Fe-Cr-B合金凝固组织由基体和硬质相组成。基体主要是马氏体和少量奥氏体组织。硬质相有M2(B,C)、M7(C,B)3和M23(C,B)6。铝的加入使Fe-12Cr-1.5B-Al合金基体转变为珠光体和铁素体组织,而对硬质相类型无明显影响。当铝含量超过6.0%时,部分铝元素与铁结合形成铁铝金属间化合物。Cr元素主要存在于硬质相中,基体中也含有一定量的Cr元素。Al元素主要存在于基体和铁铝金属间化合物中。B元素主要存在于M2(B,C)相中。无铝Fe-Cr-B合金洛氏硬度达到61.1 HRC,随着铝含量的增加,Fe-12Cr-1.5B-Al合金的洛氏硬度以及维氏硬度呈现先急剧下降后缓慢升高的趋势。

激光选区熔化成形Fe-12Cr-9Ni-2Al-1.5Mo合金的微观组织与机械性能

为满足特殊注塑模具使用性能的要求,探讨了时效处理对激光选区熔化技术(Selective laser melting,SLM)制备的Fe-12Cr-9Ni-2Al-1.5Mo合金试样微观结构和机械性能的影响.结合X射线衍射仪(XRD)、扫描电子显微镜(SEM)及电子背散射衍射仪(EBSD)等材料表征手段对SLM Fe-12Cr-9Ni-2Al-1.5Mo合金试样的物相分布、微观组织结构、拉伸断口形貌进行了对比分析.结果显示:SLM制备的Fe-12Cr-9Ni-2Al-1.5Mo合金试样经时效热处理后有少量γ-Fe相(即逆转变奥氏体)形成;SLM Fe-12Cr-9Ni-2Al-1.5Mo的平均显微硬度为(353±15.2)HV_90.2)、拉伸强度为(1090.8±5.93)MPa、延伸率为(15.7±0.33)%,时效处理后,其平均显微硬度值增加了42.5%达到(503±11.8)HV_(0.2)、拉伸强度升高到(1532.7±5.96)MPa、延伸率降低为(12.3±0.82)%;SLM Fe-12Cr-9Ni-2Al-1.5Mo合金断裂机制以韧性断裂机制为主,而时效处理后的试样则以韧-脆混合断裂机制为主,时效热处理有效提高了Fe-12Cr-9Ni-2Al-1.5Mo合金的机械性能.

Magnetic anisotropy in Fe-25Cr-12Co-1Si alloy induced by external magnetic field

Structural and magnetic properties of Fe-25Cr-12Co-1Si alloy thermo-magnetically treated under different external magnetic field conditions were investigated. Orientation and morphology of the ferromagnetic α1 phase embedded in α2 phase matrix before and after step ageing are characterized by transmission electron microscope(TEM). The results show that the ellipsoidal particles of ferromagnetic α1 phase are aligned along the direction of external magnetic field during isothermal magnetic ageing. Approximately 28% of the total coercivity can be attributed to the shape anisotropy of α1 phase particles induced by external magnetic field for Fe-25Cr-12Co-1Si alloy thermo-magnetically treated with a parallel magnetic field.

新型含铝Fe-Cr合金的热变形行为及热加工图

采用Gleeble-3500热模拟试验机对Fe-18Ni-12Cr-3Al合金进行压缩试验,其变形温度为925~1175℃、应变速率为0.01~10 s^(-1)。分析了合金真应力-真应变曲线,建立了本构方程及热加工图,并结合θ-σ曲线上的拐点,采用拐点法研究其动态再结晶的临界条件。结果表明,Fe-18Ni-12Cr-3Al合金应力随着应变速率增加和变形温度降低而升高,发生动态再结晶的临界应力和峰值应力之间具有相关性,即σ_(c)=0.95σ_(p)。依据热本构方程和热加工图,热激活能为376.1 kJ/mol,应变为0.1时的最佳热加工区域是变形温度为1110~1160℃,应变速率为0.01~1 s^(-1)。