稳定性与长程有序度的关系

利用建立在对势基础上的原子模型分析了结构稳定性与长程有序的关系,给出了二元体系结合能与有序度解析关系的一般表达式,得出有序结构必须满足n ≥ n₁>nC_A的条件,结果表明,同一合金体系中,B2结构本质上比L1₂结构更难实现从有序向无序的转变。     

非当量成分Ni3Al基合金的有序─无序转变

利用建立在EAM(Embedded Atom Method)势基础上的等效原子模型,计算了模拟非当量成分的Ni₃Al基合金结构稳定性与长程有序(LRO)度的关系,结果说明:非当量成分下,Ni₃Al基合金有序无序转变温度随Al含量的增加而上升;其有序无序转变为形核长大的非均匀转变过程,理论上不存在稳定的均匀部分有序结构;其介稳的部分状态组织为完全有序区和完全无序区的混合组织.该结果能解释实验中所观察到的Ni₃Al基合金有序无序转变。     

改善Cu坡莫软磁合金性能的工艺研究

通过对Cu坡莫合金生产工艺的系统研究，发现采用合适的冶炼工艺，提高合金的纯净度，是改善该合金加工成型性和磁性能的基础，最终的热处理是发挥材料磁性能的关键。     

钽的加工性能及应用（续）

五、精炼及深度加工各种钽的提取方法可产出品位为99.5—99.8%并或多或少地被粉化的纯钽。产自各种还原方法的粗钽的杂质成份见表3。金属钽中的杂质含量使粗钽不能直接应用。由于     

当量成分AB和A3B型合金有序─无序转变行为

利用EAM(Embedded Atom Method)势基础上的等效原子模型分析了结构稳定性与长程有序度的关系,给出了二元体系结合能与长程有序度解析关系的一般表达式,说明当量成分下AB和A₃B型合金有序无序转变行为的不同,并以NiAl和Ni₃Al为研究对象具体研究了其有序无序转变,从理论上解释了这两种有序金属间化合物在实验中所表现出的不同有序无序转变行为特征.     

低铼钼合金加工性能的研究

研究了粉末冶金法制取的低铼钼合金的加工性能。结果表明，低铼钼合金的抗拉强度和再结晶开始温度，均随着铼含量的增加而提高．在900～1400℃温度范围内，铼含量为1％、3％、5％的钼合金丝样的抗拉强度与退火温度的关系具有显著线性回归特征．     

用正电子湮没方法探测铜基合金中有序无序转变

用正电子湮没Ｄｏｐｐｌｅｒ展宽能谱，结合金相显微镜和示差热分析方法分析了一系列在不同温度处理然后淬入温室水中的Ｃｕ－２３ａｔ％Ｚｎ－１０ａｔ％Ａｌ合金试样。结果表明；该合金在９００℃处理后，降温过程中分别于７００℃～６００℃，５５０℃～５００℃，３００℃～２５０℃。发生了相变，第一个是α相变，第二和第三个是无序一有序转变，正电子湮没方法地该合金中的α相变不敏感，但对该合金中的有序－无序转变敏感。     

微晶软磁合金的交流磁性能

对四种不同含量的Ｆｅ７４Ｃｕ１Ｍ３Ｓｉ１２．５Ｂ９．５（Ｍ＝Ｎｂ＋Ｍｏ）非晶试样进行了无磁场、纵向磁场、横向磁场的热处理。测量了试样的交流复值磁导率｜μ０．３｜、矫顽力｜Ｈｃ｜和铁心损耗Ｐｃ０．２。实验结果表明：Ｆｅ７４Ｃｕ１Ｎｂ３Ｓｉ１２．５Ｂ９．５的｜μ｜０．３随频率减小的趋势最小。Ｆｅ７４Ｃｕ１Ｎｂ２Ｍｏ１Ｓｉ１２．５Ｂ９．５的｜μ｜０．３值最大，｜Ｈｃ｜和Ｐｃ０２值最小。在几种磁场热处理方法中，无磁场热处理试样的｜μ｜０．３最大，｜Ｈｃ｜和Ｐｃ０２值最小。纵向磁场热处理试样的｜μ｜０．３值最小，｜Ｈｃ｜和Ｐｃ０２值最大     

机械合金化制备Fe-Co系非晶合金

在高纯氩气保护下采用高能球磨法对原子组成为Fe44Co44Zr3.5Nb3.5B4Cu1的混合粉末进行机械合金化(MA)实验,成功地制取了非晶合金粉末.利用X射线衍射(XRD)、扫描电镜(SEM)、差热分析(DTA)对其进行测试,结果表明:Fe-Co系的混合粉末在MA过程中,通过原子之间的相互固溶、扩散可形成非晶态.此非晶合金的形成是晶粒细化、球磨过程中的缺陷、应力和致密堆垛结构等多种因素综合作用的结果,这与机械合金化的合成机理之一的扩散型机制相吻合.用非晶化的热力学条件判据和动力学条件判据对此合金进行计算,其结果也表明此合金已非晶化.     

铁钴纳米合金的制备及表征

Fe-Co合金是重要的金属软磁材料,由于具有高饱和磁感应强度、低矫顽力、高磁导率和低磁各向异性常数等独特的软磁材料性能而倍受关注。本实验以水合肼为还原剂,PVP为分散剂,采用液相还原法制备出纳米Fe-Co合金,并利用X射线衍射仪(XRD)、扫描电镜(SEM)、差示扫描量仪(DSC)对样品进行了表征。研究结果表明:制得的样品为非晶态无定形;颗粒呈球形,平均粒径为57nm;Fe-Co合金的抗氧化能力较强,在常温下不易被氧化。最后对Fe-Co纳米金属材料的发展趋势进行了展望,同时指出了Fe-Co纳米金属材料制备方法研究中存在的问题。     

Hot workability of Mg-9Y-1MM-0.6Zr alloy

The behavior evolvement of Mg-9Y-1MM-0.6Zr (WE91) alloy during hot deformation process was discussed. The flow stress behavior of magnesium alloy over the strain rate range of 0.001 to 1 s-1 and the temperature range of 653 to 773 K was studied on a Gleeble-1500D hot simulator under the maximum deformation degree of 60%. The experimental results showed that the relationship between stress and strain was obviously affected by the strain rate and deformation temperature and the flow curves observed were typical of the occurrence of dynamic recrystallization. The flow stress of WE91 magnesium alloy during high temperature deformation could be represented by the Zener-Hollomon parameter in the hyperbolic Arrhenius-type equation. The average deformation activation energy Q and strain coefficient n were 224.11 kJ/mol and 3.08 by calculation,respectively. The processing maps were calculated and analyzed according to the dynamic materials model. The map at strain of 0.916 exhibited three domains with peak efficiency of 49%,44% and 42%,respectively. It was found that the alloy could be extruded at 693 K with mechanical properties of σ0.2=240 MPa,σb=315 MPa and δ=15.5%.     

Constitution modeling and deformation behavior of yttrium bearing TiAl alloy

The deformation flow behaviors of Ti-45Al-5.4V-3.6Nb-0.3Y alloy at different temperatures and strain rates were studied by isothermal compressing simulation test.The apparent activation energy of deformation was calculated to be 402.096 kJ/mol and constitutive equation was established to describe the flow behavior.Microstructure and flow softening observations exhibited that Ti-45Al-5.4V3.6Nb-0.3Y alloy had bad hot workability at low temperature (lower than 1 100 oC) and high strain rate (higher than 0.5 s–...     

提高铝及铝合金光谱标准样品均匀性的探讨

介绍了铝及铝合金光谱标准样品的研制工序，并从标样研制工序、各元素加入方法及工序检验等方面阐述了提高光谱标样均匀性的方法，确保研制出的标准化学成分均匀，能满足光谱分析对标样的需要。     

硬质合金中氮的测定方法研究

介绍了以惰性气体脉冲加热熔融法提取氮 ,再由热导式探测器测定硬质合金中氮的方法 ,并对以Ni篮助熔剂及准确的实验分析条件 ,进行了研究     

Effect of strain rate and temperature on hot workability and flow behaviour of duplex stainless steel

The flow behaviour and processing map of a duplex stainless steel were studied via hot compressive tests in a temperature range of 1223–1473?K and a strain rate range of 0.01–30?s^??1. The effect of strain rate and temperature on the hot workability, strain partitioning and dominant flow behaviour of the alloy was systematically investigated. It is found that the softening mechanism of each constituent phase differs from each other. The ferrite is softened by dynamic recovery and continuous dynamic recrystallisation (CDRX), while the austenite is softened only by the limited discontinuous dynamic recrystallisation (DDRX). At lower strain rates (0.01 and 0.1?s^??1), the strain is mainly accommodated by ferrite due to its excellent softening capability, which causes the apparent activation energy Q_p to decline continuously with the increase in true strain. In this case, plastic deformation of the austenite rarely occurs, and at this time, DDRX of austenite is not observed. When the strain rate increases, CDRX of ferrite is weakened at a relative low temperature, which prompts the strain transfer into austenite and induces the strain hardening due to its restricted softening. Accordingly, interactions between the strain hardening in austenite and weakened softening of ferrite leads to one or more platforms of Q formed at the medium stage of deformation (1–30?s^??1). The processing map shows that two flow instability regions appear at high strain rate due to the lack of sufficient response time for dynamic restoration at the early deformation stage. As the strain increases, dynamic softening mechanism is activated at a higher temperature, resulting in a gradually narrowed flow instability region. Differently, a decrease in temperature suppresses dynamic softening of the alloy with a high strain rate, which deteriorates the hot workability of the alloy and induces microcrack formation after straining of 0.8.     

1420铝锂合金热轧工艺研究

在５００ｍｍ×１２００ｍｍ热轧机上进行１４２０铝锂合金的热轧试验,铸块加热温度３８０～４４０℃,保温时间２～１０小时。结果表明,１４２０铝锂合金适宜的热轧开坯温度为３９０～４２０℃,铸块保温时间应不小于8小时,道次压下量应控制在５％～２０％。     

Influence of cerium on hot workability of 00Cr25Ni7Mo4N super duplex stainless steel

The effect of Ce on hot workability of 00Cr25Ni7Mo4N steel melted in vacuum induction furnace was studied by Gleeble thermal simulation machine and scanning electron microscopy(SEM).The results showed that ductility of the steel with Ce addition was increased significantly because of increasing content of austenite,segregation of Ce at grain boundaries and modification of inclusion.The optimum range of Ce content in the steel was 0.030 wt.%-0.047 wt.%,and the optimum value was about 0.047 wt.%.The effect of...     

高温电热合金铁铬铝冶金工艺研究

针对铁铬铝电热合金的钢种特点,开发了精炼过程硅含量控制、VOD真空精炼铝合金化、连铸工艺及保护渣等关键技术.通过实践表明:可将铁铬铝合金中硅质量分数控制在0.15％ 以下,VOD真空条件下完成铝质量分数5％ ～6％ 的合金化,VOD精炼时间控制在60～70 min,铝收得率提高至94.5％.通过钢包稀土合金化,稀土合金...