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机械合金化过程中的金属相变 总被引:2,自引:0,他引:2
林文松 《粉末冶金材料科学与工程》2000,(4)
简述了机械合金化的工艺特点和应用,总结了机械合金化过程中的相变规律,着重分析了过饱和固溶体的形成机制及其在合金化过程中的相变过程。 相似文献
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综述了机械合金化制备Ni-Ti合金的机理、影响因素和晶化过程,可为机械合金化尤其是Ni-Ti合金化工艺参数的选择与优化提供参考. 相似文献
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机械合金化在Fe-Si合金制备中的应用 总被引:1,自引:0,他引:1
机械合金化是一种新的材料制备方法, 近年来在功能材料的制备中得到了广泛的应用. 该文简要回顾了机械合金化的发展历史, 阐述了机械合金化的原理及反应机制, 介绍了机械合金化技术在过饱和固溶体、非晶、纳米晶及金属间化合物等领域的应用状况. 指出机械合金化过程的热力学和动力学研究及合金相结构、性能与球磨工艺条件之间的规律是今后研究的重点, 后续处理工艺的改进是产品实现从实验室向工业应用转变的重要保证. 相似文献
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本文对一种氧化物弥散强化镍基高温合金的机械合金化工艺、过程及原理进行了研究。研究表明,用Cr-Ni-Al-Ti-Zr-B中间合金来代替现行的、采用多种中间合金的选配方案,可以同样获得机械合金化的效果,并能最终实现γ′沉淀相及Y_2O_3弥散相在同一合金中的均匀分布。机械合金化是在保护气氛下将各种原始粉末在高能球磨机中反复冷焊-破碎过程,以获得含有弥散质点的机械固溶体粉末。X光和扫描电镜分析表明,在“机械固溶体”中各种元素已基本合金化,同时也存在一定的微区成分偏离,但可以通过改进合金化工艺及热挤压和热处理来消除。本文也对影响机械合金化的因素进行了分析。 相似文献
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机械合金化是一种制取非晶合金的新方法。本文就机械合金化非晶转变机制、非晶合金系统、非晶形成区的实验测定和机械球磨工艺对非晶化过程的影响等问题对机械合金化非晶的研究现状作一简单综述。 相似文献
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本文报导了有关提高双层粉末冶金阀座环耐用度的研究成果。将直接浸铜工艺(DCI)和准机械合金化工艺(QMA)两者结合起来。直接浸铜工艺是在烧结过程中使铜浸渗到双层压坯的阀座一侧;准机械合金化工艺可降低高合金化过程中的生产成本。 相似文献
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机械合金化制备纳米晶硬质合金粉的进展 总被引:2,自引:0,他引:2
综述了机械合金化制备纳米晶硬质合金粉的概况、原理和两种用该方法制备纳米晶硬质合金粉的方式。并分析了各工艺参数对机械合金化制备纳米晶硬质合金粉的影响。该技术工艺简单,可实现工业化生产,是一种很有应用前途的方法。 相似文献
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Vaporization of alloying elements is a serious problem in the laser welding of many important engineering alloys. Since the
available mass transfer correlations are not applicable for credible assessment of the rates of transport of vaporized species
in the gas phase, the role of gas phase mass transfer in the overall vaporization of alloying elements was examined by conducting
several critical experiments. The rates of transport of alloying elements in the weld pool were determined from numerically
computed fluid flow fields. Since the weld pool is surrounded by plasma during laser welding, the role of plasma in the vaporization
of alloying elements was physically modeled by allowing molten copper drops to vaporize isothermally both in the presence
and absence of plasma. The transport of alloying elements in both liquid and gas phases was found to be rapid and the overall
vaporization rates were controlled by the plasma influenced intrinsic vaporization of alloying elements at the weld pool surface.
The experimentally obtained rates of vaporization of alloying elements from laser melted stainless steel weld pools were compared
with the corresponding theoretically calculated values. 相似文献
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P. G. Ovcharenko A. Yu. Leshchev K. E. Chekmyshev T. M. Makhneva 《Russian Metallurgy (Metally)》2017,2017(11):980-983
The main stages of titanium boride formation in alloyed surface layers on iron–carbon alloy castings are considered. Surface alloying was performed by self-propagating high-temperature synthesis in alloying compositions during lost-foam casting. Titanium and ferrotitanium are used in alloying compositions to ensure synthesis, which is initiated by the melt thermal energy during casting formation. The thermal effects of the main reactions of titanium boride formation in various alloying compositions are compared. The microstructure, the phase composition, and the hardness of the alloyed surface layers are studied. 相似文献
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在45#钢基体上采用等离子束合金化法制备AlCoCrCuFe_xMnNi高熵合金涂层。采用SEM,EDS,XRD等研究高熵合金涂层的组织,利用显微硬度计测试涂层的显微硬度分布。结果表明:采用等离子束合金化Al,Co,Cr,Cu,Mn和Ni等摩尔单质金属粉,在等离子束作用下45#钢基材中的Fe元素参与表面合金化,形成了厚度约为1 mm的AlCoCrCuFe_xMnNi七主元高熵合金涂层,涂层主要由BCC结构的枝晶和FCC结构的枝晶间组织组成。另外,还有σ相主要分布在枝晶间,涂层从表面到基材,体系的混合熵呈高熵-中熵-低熵梯度变化。涂层的维氏显微硬度(HV0.2)达到670~400的梯度分布。 相似文献
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《Scripta Metallurgica et Materialia》1995,32(4):595-600
The PbTe intermetallic compound could be fabricated by mechanical alloying of elemental Pb and Te powders for 2 minutes at ball-to-powder weight ratio of 2 : 1. The lattice parameter of PbTe processed by mechanical alloying, 0.6462 nm, was in excellent agreement with the value of 0.6458 nm which was reported for PbTe powder fabricated by melting and grinding. In situ observation of the abrupt temperature rise during the ball milling process indicated that the PbTe intermetallic compound was formed by a self-sustained reaction rather than by diffusional reactions. There was no tendency for PbTe crystalline powders to be amorphized by mechanical alloying. 相似文献
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Mechanical alloying of brittle materials 总被引:7,自引:0,他引:7
R. M. Davis B. McDermott C. C. Koch 《Metallurgical and Materials Transactions A》1988,19(12):2867-2874
Mechanical alloying by high energy ball milling has been observed in systems with nominally brittle components. The phases
formed by mechanical alloying of brittle components include solid solutions (Si + Ge → SiGe solid solution), intermetallic
compounds (Mn + Bi → MnBi), and amorphous alloys (NiZr2 + Ni11Zr9 → amorphous Ni50Zr50). A key feature of possible mechanisms for mechanical alloying of brittle components is the temperature of the powders during
milling. Experiments and a computer model of the kinetics of mechanical alloying were carried out in order to esti-mate the
temperature effect. Temperature rises in typical powder alloys during milling in a SPEX mill were estimated to be ≤350 K using
the kinetic parameters determined from the computer model. The tempering response of fresh martensite in an Fe-1.2 wt pct
C alloy during milling was consistent with the maximum results of the computer model, yielding temperatures in the pow-ders
of ≤575 Ki.e., ΔT ≤ 300 K). Thermal activation was required for mechanical alloying of Si and Ge powder. No alloying occurred when the
milling vial was cooled by liquid nitrogen. The pos-sible mechanisms responsible for material transfer during mechanical alloying
of brittle components are considered. 相似文献
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利用辉光放电光谱法测定合金化镀锌板镀层中铁含量,根据样品由表至里的辉光放电积分图谱,分别积分计算镀层中锌、铝、合金化铁的质量,从而得到镀层中真实的铁含量。同时,根据GB/T 1839的镀锌表面处理办法将合金化镀锌板镀层全部溶出,采用ICP AES法测定镀层中铁的百分含量。结果发现,辉光放电光谱法与ICP AES法对两块试样分别进行6次测定,相对标准偏差分别为16%、19%和16%、031%,辉光放电光谱法测定结果与ICP AES法偏差分别为032%和048%。通过这种方法比对,还可以在采用辉光放电光谱法对非典型合金化镀锌板进行分析时优化积分参数,确保在线生产检验的连续性及准确性。 相似文献