Structure of a titanium-alloyed high-tin bronze obtained by the Osprey method

The titanium-alloyed bronzes with enhanced (14.5 and 15.5 wt %) tin content obtained by the Osprey method have been studied by the methods of optical, scanning, and transmission electron microscopy with the use of quantitative microanalysis in the initial state and after hot extrusion. These alloys have been employed as bronze matrices of multifilamentary superconducting Nb/Cu-Sn composites. An increase in the tin content in the bronze matrix makes it possible to enhance the critical current density of the multifilamentary composite owing to the improvement of the structure and composition of a superconducting Nb₃Sn compound that is formed upon diffusion annealing. It has been shown that the Osprey technology allows one to obtain bronzes with an enhanced Sn content and simultaneously to reduce the dendritic segregation characteristic of cast bronzes. The distribution of Sn and Ti in these alloys has been investigated. A more homogeneous structure in the initial state is characteristic of the alloy Cu-14.5Sn-0.24Ti (wt %). The increase in the tin content to 15.5 wt % leads to the formation of microregions of dendritic segregation with an (α + δ) eutectoid in the initial state, which slightly decreases plastic characteristics of this bronze.     

Study of adhesion of liquid-glass masonry mortar to acid-proof ceramics in anticorrosion linings

A technique for determining the adhesion of a liquid-glass masonry mortar to acid-proof ceramics in anticorrosion linings is described. The results of studying adhesion in the linings under the action of certain types of chemically aggressive environments are given.     

Modification of iron surface by dimegin and adsorption of 1,2,3-benzotriazole

The preapplication of dimegin on the passive iron surface is shown to enhance adsorption of 1,2,3-benzotriazole (BTA). The adsorption of BTA on passive iron and its surface preliminarily modified by chemisorption of dimegin can also be adequately described by the Temkin equation. The adsorption characteristics of BTA depend on the degree of filling of the iron surface with dimegin. Upon the transition to the modified surface, the factor of its heterogeneity initially increases (to θ_DMG ≈ 0.5), then decreases.     

Adjusting the linear expansion coefficient Lin Fe-Ni-Co-Ti invars by aging and phase hardening

The N30K10T3 and N40K10T3 invars with the Curie points θ_C ≈ 200°C and θ_C ≈ 310°C and the martensite temperatures M _s ≈ −80°C and M _s < −196°C, respectively, have been studied. The two alloys were hardened by quenching in the range of temperatures from 100 to 750°C. In addition, the first alloy was hardened by a combination treatment including phase-transformation-induced hardening and aging. The method of phase hardening consisted in the use of a forward (γ → α) and a reverse (α → γ_ph) martensitic transformations. It has been shown that the temperature dependences of the linear expansion coefficient and the dependences of the hardness on the temperature and time of aging are considerably different for both alloys upon decomposition of the supersaturated solid solution. Both the ordinary and the double aging have been studied.     

深过冷Ni-21.4%Si共晶合金的凝固特性研究

对熔融玻璃净化后深过冷Ni-21.4%Si（原子分数,下同）共晶合金的凝固特性进行了实验研究,并对其均质形核过冷度进行了理论预测.结果发现,采用熔融玻璃净化可使Ni-21.4%Si共晶合金获得318 K的过冷度.理论计算表明,此过冷度达到了Ni-21.4%Si共晶合金的均质形核过冷度.Ni-21.4%Si共晶合金凝固特性与过冷度△T有关:当过冷度小于250 K时,冷却曲线有2个再辉峰,其中当过冷度小于206 K时,凝固组织由Ni3Si相和规则共晶组成,当过冷度在206 K到250 K之间时,凝固组织由α-Ni相和规则共晶组成;过冷度大于250 K后,冷却曲线只有1个再辉峰,凝固组织为反常共晶.过冷度会影响初生相Ni3Si的生长方式.随着过冷度的增大,初生相Ni₃Si的生长会由小平面生长方式转为非小平面生长方式.     

Application of the Same-Stuff and Equal-Strength Laser Cladding Technology on the Repaired Semishrouded Impeller

0Cr17Ni4Cu4Nb powder was used to investigate the same-stuff laser repair(LR)technology on the semishrounded impeller.To improve the repaired effect,heat treatment was used after LR forming process.By means of optical microscopy,scan electron microscopy(SEM),micro-hardness tester and tensile tests,the microstructure of the coating was investigated and mechanical properties were measured.The experimental results show that cladding layer is well bonded to the substrate,the microstructure of the laser repaired zone(LRZ)is coarse martensite which will be refined after heat-treatment.The mechanical property experiments indicate that the micro-hardness and toughness would be increased after heat-treatment,the strength of LRZ after heat-treatment is 1050～1200 MPa,while the strength of normal laser repaired sample is 1000～1050 MPa.The refinement effect due to the heat treatment plays an important role in the improvement of the mechanical properties of samples.Overspeed examination and the real operation of the impeller after repairing also confirmed the reliability of this same-stuff and equal-strength laser cladding technology.     

不同形态和热历史条件下Zr55Al10Ni5Cu30非晶合金的晶化行为

研究了不同形态Zr₅₅Al₁₀Ni₅Cu₃₀非晶合金（块体和粉末）在不同升温和冷却条件下的晶化行为.发现Zr₅₅Al₁₀-Ni₅Cu₃₀在不同热历史下的晶化行为有较大差别.对于块体非晶合金,在常规热处理条件下,合金的升温和冷却速率较低,Zr₅₅Al₁₀Ni₅Cu₃₀块体非晶合金在初始晶化温度Tx以上开始晶化,形成CuZr₂纳米晶.随着热处理温度的升高,晶粒尺寸增大,当热处理最终温度超过熔点后,合金在随炉冷却过程中形成了粗大的CuZr₂板条+板条间（CuZr₂）+（Zr,Cu,Al,Ni）共晶组织;在激光熔凝条件下,合金的升温和冷却速率较高,Zr₅₅Al₁₀Ni₅Cu₃₀块体非晶合金随单点熔凝次数的增加,晶化效应逐渐累加,热影响区中逐渐出现微米级球晶的弥散析出,并长大,随后失稳形成沿熔池边界带状分布,尺寸可达几百微米的等轴晶.对于粉末非晶合金,由于Zr₅₅Al₁₀Ni₅Cu₃₀非晶粉末的冷却强度不如块体非晶,冷却速率较块体低,造成粉末颗粒在激光熔凝过程中晶化为微米级的等轴枝晶,并随着激光能量的升高,等轴枝晶尺寸增大.     

Force generation during friction stir welding of AA2024-T3

Force measurement in friction stir welding (FSW) provides a significant insight into the process in terms of machine and tool limitations and design. In the present research the tool forces were investigated experimentally using a rotating component dynamometer and through the development of a finite element model. The model correlated well with experimental temperatures and tool forces and was capable of predicting tool forces for different welding parameters, predicting regions were tool failure is likely to occur and identifying tool pin designs which can process the workpiece more efficiently.     

X65MS管线钢的动态连续冷却转变

基于Gray博士的低碳低锰专利设计X65MS管线钢的合金成分,通过Gleeble-3800热模拟试验机研究形变奥氏体的相变规律。将得到的膨胀量曲线,结合各个冷速下的金相显微组织以及显微硬度,绘制出CCT曲线。结果表明,对于该成分的X65MS管线钢,在40 ℃/s的冷却速度下,能够得到较高的抗H2S腐蚀性能的单相贝氏体显微组织。同时,终冷温度不得低于480 ℃,以防止因为马氏体组织的出现而引起组织不均匀性,降低管线钢的抗H2S腐蚀性能。