灰铸铁件表面铁素体层及过冷石墨形成机理及消除对策

阐述了灰铸铁件表面铁素体层和过冷石墨产生的原因及其对铸件力学性能的影响,提出了消除和防止对 策:合理配方是基础,复合孕育是关键,适量的合金化是保障。     

大块深过冷Ni基合金的细晶化

用玻璃熔剂净化大体积Ni_77Si_13B_10合金液实行深过冷,以研究大块深过冷合金细晶化与过冷度、再辉形态及冷却速率的关系。实验发现,大体积深过冷合金细晶化具有明显的不均匀性。提出了造成这一结果的原因及解决途径。     

机械过冷的制冷系统在汽车空调中的应用

由于很多汽车空调采用斜盘式压缩机，有利于采用机械过冷的制冷系统，来增加汽车空调的制冷量、提高制冷效率。本文的主要目的是通过对系统工质的流量分配、空调制冷量和性能系数(COP)与中间压力之间的变化关系的研究，来研究机械过冷在汽车空调中应用的可行性。     

Structures of bulk amorphous Zr41Til4Nil0Cul2.5Be22.5 alloy in amorphous, crystalline, supercooled liquid and liquid states

The amorphous and crystal structures of Zr41Til4Nil0Cul2.5 Be22.5 alloy have been analyzed with X-ray dif[ractometer. The structures of bulk amorphous Zr41Til4 Nil0Cul2.5B22.5 alloy in solid, supercooled liquid and liquid states are almost of the same structure. The RDFs (Radius Distribution Function), the first coordination number, the first coordination radius, the correlation radius and atom number of the cluster were calculated for bulk amorphous Zr41Til4Nil0Cul2.5B22.5 alloy in different states. The first coordination sphere radii and the first coordination numbers are 0.312nm, 11.2 in solid state, 0.301 nm, 10.932 in supercooled liquid region and 0.305nm, 11.296 in liquid state.The crystal structure of Zr41Til4Nil0Cu12.5B22.5 alloy is consisted of several intermetallic compounds which are CuZr2,Be2Zr, etc. The reason of formation glass for this alloy is that there is a larger resistance for atoms to rearrange and form intermetallic comnounds in a long range order.     

铸轧铝板坯晶粒度的控制

晶粒度是影响铸轧铝板坯性能的重要因素。论述了铸轧铝板坯产生粗大晶粒的主要原因及其预防措施。     

熔剂净化对Al－4．5wt％Cu合金过冷及组织的影响

采用盐类熔剂对大体积Ａｌ－４．５ｗｔ％Ｃｕ合金进行净化处理，研究了熔剂净化对Ａｌ－４．５ｗｔ％Ｃｕ合金过冷及组织的影响。通过大量的实验研究证明：粘性熔剂更能有效地去除合金中的异质核心，使合金获得较大的过冷度；随着过冷度的增大，合金的宏观组织由细小的等轴晶逐渐过渡到粗大的柱状晶，其临界转变过冷度为４０℃；二次枝晶间距随过冷度的增大而增大，其转变过冷度为５０℃。     

共晶自生复合材料的晶形转变

自生复合材料的晶形转变受到成分过冷与曲面过冷两个因素的控制.非金属相具有较大的熔化熵且易形成小平面是改变领先相的因素,而领先相的改变则可能是晶形转变的根本原因.     

深过冷Fe76B12Si12超细晶材料的凝固组织与软磁性能

首次采用深过冷加水淬的方法,成功地制备了直径为16 mm的样品,高为15 mm,组织中颗粒平均尺寸约为120nm左右的Fe76B12Si12合金超细晶材料.其磁损耗P1T400和P1T1000分别为普通硅钢片的40%和65%.系统研究了组织类型及Fe2B(Si)相尺度对该合金软磁性能的影响,发现该合金的最佳软磁性能位于Fe2B(Si)相完全粒化的非规则共晶组织区,并且当Fe2B(Si)相尺寸细化至0.36～0.50μm时,其软磁性能随着相尺寸的减小而大幅度改善.对以上结果产生的原因进行了讨论.     

疏水阀性能对生产工艺的影响

按生产工艺的需要选择合适的疏水阀才能充分发挥设备的能力、节约能源和提高热效率。本文从疏水阀的过冷度、背压度、漏气率及使用寿命等项工作性能的角度探讨了各种类型的疏水阀所适用的工艺要求,从而介绍了自由浮球式疏水阀优良性能。     

MICROSTRUCTURAL EVOLUTION OF HIGHLY UNDERCOOLED EUTECTIC Ni78.6Si21.4 ALLOY

A large undercooling level up to 550K （0.386Te） was achieved in eutectic Ni78.6Si21.4melt by the combination of molten-glass and cyclic superheating. A microcrystaUine structure is obtained at large undercooling. Surprisingly, the morphology of ct（Ni） phase transits from the non-faceted phaseto faceted phase at large undercooling of 390K. Based on the classical nucleation theory and transient nucleation theory, the process of microstructure evolution and competitive nucleation was analyzed, and the refinement of crystal structure is determined by the high nucleation rate under large undercooling.