微波热凝固处理对肿瘤的杀伤及免疫效应

实验以负荷ＳＣＣ－８９１乳腺癌小鼠为对象，用袖针插入式针形辐射器为天线，对肿瘤进行微波热凝固处理（ＭｉｃｒｏｗａｖｅＴｉｓｓｕｅＣｏａｇｕｌａｔｉｏｎＭＴＣ），观察微波对肿瘤的杀伤及其作用后的免疫效应。病理切片及各组ＩＬ－２，ＩＬ－２Ｒ，ＳＩ的动态结果表明，ＭＴＣ能直接杀伤肿瘤细胞，对荷瘤鼠细胞免疫功能的进行性下降有抑制，具有类似免疫活性剂的作用。

齿轮的微秒熔化凝固处理

本文着重介绍金属材料表面经快速熔化再凝固 ( RMRS)

磁场凝固处理对稀土铝合金电化学性能的影响

在Al-In-Zn-Sn合金的基础上,掺入Ce形成合金样品,将样品进行重熔与磁场凝固处理制成研究电极,通过SEM对其表面形态进行了分析,并在4 mo.lL-1的KOH溶液中进行阳极极化曲线、交流阻抗、恒流放电等电化学性能测试。结果表明:磁场凝固处理能够提高Al-In-Zn-Sn-Ce合金的腐蚀电位,减小阳极材料的阻抗,改善阳极的放电性能。

快速冷却条件下凝固潜热处理模型的研究

深入分析了有限差分法模拟凝固过程时,采用等效比热法处理相变潜热的原理;从理论和实际计算角度分析了快速冷却条件下常规的等效比热法会造成热量"虚增",模拟计算结果失真的原因和影响程度;并进一步建立了快速冷却条件下凝固潜热处理的模型。计算结果表明,该模型可以充分保证模拟计算的精度和效率。

高温热处理对(DS)NiAl-Cr(Mo)-Hf共晶合金显微组织和显微硬度的影响

采用高温度梯度定向凝固装置制备NiAl-28cr-5Mo-1Hf(原子分数,％,下同)共晶合金,研究了高温热处理对合金显微组织和显微硬度的影响。结果表明,热处理后,NiAl和Cr(Mo)的层片状组织形貌基本没有变化,而合金中分布于胞界的半连续的Heusler(Ni_2AlHf)相部分或大部分消失,并以弥散的Heusler颗粒形式在NiAl基体中重新析出。此外,Cr(Mo)相中的NiAl微粒粗化,在Cr(Mo)相中出现了位错线,定向凝固NiAl-28Cr-5Mo-1Hf合金的显微硬度明显高于NiAl-28Cr-6Mo合金,热处理后,合金的硬度值基本保持不变。

镁的应用及其腐蚀与防护

对镁及镁合金的性能、应用现状和前景及其腐蚀问题和防护方法进行了综述 ,如 :高纯合金或新合金、快速凝固处理。

Microstructure of cast γ-TiAl based alloy solidified from β phase region

The microstructures and phase transformation of Ti-43Al-4Nb alloy in as-cast and heat-treated states were investigated by using optical microscopy, scanning and transmission electron microscopy as well as differential scanning calorimetry. The results show that a fine microstructure of the as-cast alloy can be obtained by solidifying through the β phase. γ grains can nucleate directly from the β phase. The coexistence of β phase and γ phase along primary α grain boundaries contributes to the decrease in the grain size of the as-cast alloy. The phase transformation sequence during solidification of the Ti-43Al-4Nb alloy is suggested as L→L＋β→β→α＋β→α＋βr→α＋γ＋βr→lamellae（α2＋γ）＋γ＋βr. The microstructure of the alloy after heat treatment at 1 250 ℃ for 16 h exhibits a certain coarsening compared with that of the as-cast state. The remnant β phase can be removed by the heat treatment process due to the diffusion of Nb and the non-equilibrium state of β phase.

Effects of heat treatment on microstructure of directionally solidified Ti-45Al-8Nb-(W,B,Y) alloy

The effects of heat treatments on typical microstructures of directionally solidified（DS） Ti-45Al-8Nb-（W,B,Y）（molar fraction,%） alloys prepared by the Bridgeman method were studied.Two typical DS microstructures including full lamellae with cellular growth morphology and massive structure with dendritic growth morphology were examined.The results show that the heat treatment of 1250 ℃ for 24 h ＋ 900 ℃ for 30 min＋air cooling can efficiently eliminate the B2 phase in the DS alloys and change the massive structure of the rapid DS alloy into lamellar microstructure.Columnar lamellar colonies with widths of 150-200 μm and 50-100 μm respectively were observed in intercellular and dendritic arm regions.The heat treatment of 1 400 ℃ for 12 h＋900 ℃ for 30 min＋air cooling could simultaneously remove the B2 phase,massive structure and solidification segregations from the DS alloys,however,it caused severe growth of grains.

Effects of P and B addition on as-cast microstructure and homogenization parameter of Inconel 718 alloy

The effects of phosphorus and boron addition on the as-cast microstructure and homogenization parameters of Inconel 718 were studied. The results indicate that the addition of phosphorus and boron promotes the formation of blocky Laves phase. Due to the strong segregation behavior of boron in the final residual liquid, a low melting B-bearing phase enriched in Nb, Mo and Cr is observed. According to the differential scanning calorimeter results and electron probe micro-analysis characterization, the solidification sequence of Inconel 718 with phosphorus and boron addition in best combination is determined as L→L＋γ→L＋γ＋MC→L＋γ＋MC＋Laves→γ＋MC＋Laves＋MC＋Laves＋B-bearing phase. Accordingly, the homogenization temperature is recommended to be adjusted at least 40°C lower than that of standard Inconel 718 due to the existence of low melting B-bearing phase.

Grain refinement of pure aluminum by direct current pulsed magnetic field and inoculation

The combined effects of direct current pulsed magnetic field （DC-PMF） and inoculation on pure aluminum were investigated, the grain refinement behavior of DC-PMF and inoculation was discussed. The experimental results indicate that the solidification micro structure of pure aluminum can be greatly refined under DC-PMF. Refinement of pure aluminum is attributed to electromagnetic undercooling and forced convection caused by DC-PMF. With single DC-PMF, the grain size in the equiaxed zone is uneven. However, under DC-PMF, by adding 0.05% （mass fraction） Al5Ti-B, the grain size of the sample is smaller, and the size distribution is more uniform than that of single DC-PMF. Furthermore, under the combination of DC-PMF and inoculation, with the increase of output current, the grain size is further reduced. When the output current increases to 100 A, the average grain size can decrease to 113 μn.

Solidification behaviour of Al-7%Si-Mg casting alloys

The effects of Mg content and cooling rate on the solidification behaviour of Al-7%Si-Mg（mass fraction） casting alloys have been investigated using differential scanning calorimetry, differential thermal analysis and microscopy. The Mg contents were selected as respectively 0.00%, 0.35% and 0.70%（mass fraction）. DTA curves of Al-7%Si-0.55%Mg（mass fraction） alloy at various cooling rates were accomplished and the alloy melt was cast in different cooling rates. The results indicate that increasing Mg content can lower the liquidus and binary Al-Si eutectic transformation temperatures. Large Fe-rich π-phases （Al8FeMg3Si6） are found in the 0.70% Mg alloys together with some small β-phases （Al5FeSi）; in contrast, only β-phases are observed in the 0.35% Mg alloys. The test results of the Al-7%Si-0.55%Mg alloys identify that the liquidus and binary Al-Si eutectic transformation temperatures decrease, and the quantity of ternary Al-Si-Mg2Si eutectic phase decreases as the cooling rate increases.

Effect of cyclic heat treatment on microstructures and mechanical properties of directionally solidified Ti-46Al-6Nb alloy

The Ti-46A1-6Nb （mole fraction, %） ingots that were directionally solidified by cold crucible were cyclic heat treated at 1330 ℃ in the a phase region. The microstructures and mechanical properties of the ingots before and after heat treatment were investigated. The results show that the large columnar grains are changed into equiaxed grains after heat treatment. The grain size decreases with increasing the cyclic times, which is caused by the recrystallization and the transition from the large grain of small lamellae to the small grain of large lamellae. Four times of cyclic heat treatment refines the grain size from 1.33 mm to 0.59 turn, nevertheless the lamellar spacing increases from 0.71 ~tm to 1.38 lim. Extending the holding time and increasing the cyclic times of heat treatment eliminate the fl-segregation at the grain boundary and the interlamellar. The compression testing shows that the compressive strength of the directionally solidified ingot in the parallel and perpendicular directions are 1385.09 MPa and 1267.79 MPa, respectively, which are improved to 1449.75 MPa and 1527.76 MPa after two and four times of cyclic heat treatment, respectively, while that is 1180.64 MPa for the as-cast sample. The fracture mode of the sample after cyclic heat treatment is quasi-cleavage fracture.

Microstructure optimization of directionally solidified hypereutectic Nb-Si alloy

Nb-16Si-24Ti-10Cr-2A1-2Hf alloy was directionally solidified with withdrawal rates of 1.2, 6, 18, 36 and 50 mrn/min and then heat treated at 1400, 1450 and 1500℃with withdrawal rate of 50 mm/min for 10 h. The effects of withdrawal rate and heat treatment temperature on the microstructure were studied. The microstructure of directionally solidified alloy was composed of the primary NbsSi3, Nbss/NbsSi3 eutectic cells and Cr2Nb, which distribute paralleled to the growth direction. The microstructure becomes more refined with the increasing withdrawal rate, accompany with the evolution of eutectic cells morphology. After heat treatment, Nbss phase connects and forms a continuous matrix, and the Cr2Nb phase becomes smaller and distributes more dispersedly. After heat treatment at 1450 ℃ for 10 h, the alloy achieves balance between the optimization of microstructure and alleviation of solute segregation.

Effect of complex modification of Al-5Ti and Al-3P on hypereutectic Al-18Si alloys

The solidification microstructure,fracture morphologies,and mechanical properties of an Al-18Si alloy and alloys modified with Al-5Ti and Al-3P master alloys were investigated using an optical microscope,scanning electron microscope,and an electronic universal testing machine.The results show that additions of Al-5Ti and Al-3P have significant effects on the size and area fraction of the primary Si and the mechanical properties of the Al-18Si alloy.Compared to the Al-18Si alloy modified with 0.6 wt%Al-5Ti at 850°C,when the Al-18Si alloy was modified with 0.3 wt%Al-5Ti and 0.5 wt%Al-3P at the same temperature,the average size of the primary Si decreased from 39 to 14μm and the area fraction increased from 9.5%to 11.6%.The biggest influencing factor on the tensile strength and elongation of the Al-18Si alloy is the addition of Al-3P,followed by the modification temperature and the addition of Al-5Ti.At a modification temperature of 850°C,the tensile strength and elongation of the Al-18Si alloy modified with 0.3 wt%Al-5Ti+0.5 wt%Al-3P increased by 19.6%and 88.6%,respectively compared to that of the Al-18Si alloy modified with 0.6 wt%Al-5Ti.

Experimental Study of Wastewater Treatment of Reactive Dye by Phys-Chemistry Method

Wastewater, which involves easy-soluble reactive dyes, especially non-degradable dyes, is very difficult to decolor efficiently by normal processes such as coagulation process and biological treatment. The high chromaticity se- riously hinders the reuse of reactive dye waste water. In this paper, a new method by bentonite adsorption and coagulation (PAC) is employed for removing color from synthetic dye waste water which contains reactive red K-2G, K-RN blue, K-GR blue, X-3B red, K-GN orange, KB-3G yellow, K-2BP red, K-RN yellow and K-6G yellow. Bentonite pre- treated by 4% CTMAB and milled to 160 order screen is proven to the best decoloring agent. For a 100 mL reactive red K-2G sample (CODcr 400 mg/L, 25 000 chromaticity color), 0.5 g bentonite pretreated and 2.5 mL PAC is enough to decolor wastewater up to 99.92% and the sediment time is short. Non-degradable dyes such as active red X-3B and K-GN orange are declored completely as well. Raw sewage (low chromaticity color) is decolored completely at a ben-tonite dosage of 0.001g. More researches prove the high practical value of this process.

Microstructural evolution and mechanical properties of forgedβ-solidifiedγ-TiAl alloy by different heat treatments

The microstructural evolution and tensile properties of a forged Ti−42Al−5Mn alloy subjected to different heat treatments were studied.The results showed that,when the forged alloy was aged at 800℃ for 24 h,the interlamellar spacing(λ)andγgrain size at colony boundaries are generally coarsened.Whereas,when the alloy was first annealed at 1300℃ and then aged at 800℃ for 24 h,this coarsening of related microstructures appears less pronounced.The suggested annealing temperatures for the forged Ti−42Al−5Mn alloy are in the range of 1250−1300℃.It was found that,on the condition of the same annealing system,both the strength and ductility were improved as the aging temperature changed from 1000 to 800℃.The secondary precipitatedβo(β_(o,sec))at colony boundaries could be responsible for improving the strength,and theγphase at colony boundaries with the grain size about 6μm might be one of the main reasons for the better ductility.

Standard heat treatment effects on TLP bonded IN-738LC superalloy using BNi-9 filler:An approach to make an ideal joint

The present research is focused on the effects of standard heat treatment on the microstructure and mechanical properties of diffusion brazed IN-738 LC superalloy.Three distinct heat treatment cycles of full solution annealing,partial solution annealing,and aging treatment were applied to the bonded specimens,sequentially.The results reveal that bonding at 1120℃for 5 min leads to incomplete isothermal solidification and formation of eutectic phases including Ni-and Cr-rich borides in the joint centerline.Increasing the holding time to 45 min leads to the full isothermal solidification and formation of a nickel proeutectic solid-solution phase(γ)in the joints.The standard heat treatment of isothermally solidified and non-isothermally solidified specimens results in the complete elimination of the boride phases in the diffusion-affected zone and also the formation ofγ’precipitates in the isothermally solidified zone.However,discontinuously re-solidified products are observed in joint district in the non-isothermally solidified sample.The highest shear strength(~801 MPa)is achieved for isothermally solidified specimen after standard heat treatment;this strength is approximately 99%that of the substrate material.

GPU-accelerated phase field simulation of directional solidification

The phase field simulation has been actively studied as a powerful method to investigate the microstructural evolution during the solidification.However,it is a great challenge to perform the phase field simulation in large length and time scale.The developed graphics processing unit(GPU)calculation is used in the phase filed simulation,greatly accelerating the calculation efficiency.The results show that the computation with GPU is about 36 times faster than that with a single Central Processing Unit(CPU)core.It provides the feasibility of the GPU-accelerated phase field simulation on a desktop computer.The GPU-accelerated strategy will bring a new opportunity to the application of phase field simulation.