Morphology and kinetics evolution of γ′ and γ phases in Ni-xAl-(20-x)Cr at % alloys

The morphology and kinetics evolution of γ’ and γ phases in Ni-xAl-(20-x)Cr at%(x=7.5-13.7) alloys aged at700℃ were studied by utilizing the phase-field simulation.The separated γ’ phases from γ matrix in low Al content(x <13) alloys transferred to the interconnected morphology with separated y phases in high Al content(x> 13) alloys,and long-time aging produced near cubic γ’ phase.The coarsening rate of γ’ phase declined firstly when the Al content x=7.5-9.0,then increased sharply as x ra...     

一种1Cr18Ni9不锈钢基片PTC厚膜电路的实现方法

为了将PTC(positive temperature coefficieat)电子浆料以厚膜电路的形式制备在不锈钢基片上,并把不锈钢本体作为散热器,引出电极利用PTC效应制成可控电热元件.方法:提出基于1Cr18Ni 9不锈钢基片的PTC厚膜电路的组成结构,并根据1Cr18Ni 9的膨胀系数和电路元件的电气特性实现了厚膜电路PTC电子浆料的应用设计技术.结果显示以PTC厚膜电路材料组成的可控电热元件,其功率密度高达200 W/cm2;其电阻膜层的表面加热速度可达200-300℃/s;其使用寿命达到1 万小时以上.可见与传统的电热合金材料、陶瓷基片加热器以及元件组合的加热器相比,本实现技术电路具有功率密度大、响应速度快、加热温度可控等优点.     

强韧化处理对3Cr2W8V热锻模寿命的影响

通过对 ３ Ｃｒ２ Ｗ８ Ｖ 热锻模失 效组织 的电镜 观测 和 对断 裂韧 性 Ｋ Ｉ Ｃ 值的 测定 ，认 为 Ｋ Ｉ Ｃ 值 偏 低是３ Ｃｒ２ Ｗ８ Ｖ 热锻 模早期开 裂和热 疲劳的主 要原因 实践 证明， 采用 １ ２００ ℃ 高 温淬 火 和６８０ ℃高 温 回火（ 即高淬 高 回） 的 新 工 艺， 能 大 幅 度 提 高 材 料的 Ｋ Ｉ Ｃ 值， 延 长 该 类 模 具 寿 命 ４ 倍 左 右  因 而 Ｋ Ｉ Ｃ 值 是３ Ｃｒ２ Ｗ８ Ｖ 热锻 模的主 要韧性指 标，而冲 击韧性α Ｋ 值仅 能作为 参考图 ２ ，表 １ ，参６      

Hydrogen absorption-desorption characteristic of (Ti0.85Zr0.15)1.1Cr1-xMoxMn based alloys with C14 Laves phase

The microstructure and hydrogen absorption-desorption characteristic of (Ti_0.85Zr_0.15)_1.1Cr_1-xMo_xMn (x ?= ?0.05, 0.1, 0.15, 0.2 ?at.%) alloys were investigated. The results showed that the corresponding alloys were determined as a single phase of C14-type Laves structure. With the increase of Mo content, the maximum and reversible hydrogen absorption capacity decreased, the slope factor H_f increased. Among the studied alloys, (Ti_0.85Zr_0.15)_1.1Cr_0.95Mo_0.05Mn had the best overall properties for practical application of hydrogen storage materials. The maximum and reversible hydrogen storage capacity were 1.76 ?wt% and 1.09 ?wt%, the slope factor H_f was 0.51, and its dissociation enthalpy (ΔH_d) and entropy change (ΔS_d) were 23.1 ?kJ ?mol^?1H₂, 93.8J ?K^?1mol^?1H₂ at 303K, respectively. By studying the dissociation pressures of the synthesized metal hydrides, it was found that Mo had a special effect on the dissociation pressure of Ti–Zr–Cr–Mo–Mn alloys. Among the four alloys, (Ti_0.85Zr_0.15)_1.1Cr_0.95Mo_0.05Mn alloy had the largest hydrogen absorption capacity and the fastest hydrogen desorption rate, which can meet the commercialization demand of hydrogen fuel cell hydrogen supply system.