Au与Au合金材料近年的发展与进步

总结与评述了自本世纪以来Au与Au合金材料在科学技术与应用方面取得的一些新进展,其内容包括Au与Au合金冶金学研究、Au与Au合金新材料和新的加工制备技术3个方面.在冶金学方面,简单介绍了某些新的Au合金相图研究和Au合金向多元合金化和微合金化方向的发展.新的Au与Au合金材料研究包含电气工业用新材料、电子工业用新材料、饰品与牙科新材料及先进复合材料和涂层材料等.Au材料的加工技术也获得了新的发展.最后,总结和评述了Au与Au合金材料应用的发展趋势.     

均匀化热处理对牙科烤瓷无钯高金合金组织性能的影响

研究了均匀化热处理对一种无钯牙科高金烤瓷合金组织性能的影响,对其进行了950℃保温30min的均匀化处理,然后快速在冰水混合物中淬火,并对之做了一系列测试分析.实验结果显示合金在均匀化热处理后,组织显著均匀化,硬度显著降低.淬火后的合金仍为α1和α2两相组织,但富铂的α2相颗粒的量比铸态组织明显减少,颗粒的尺寸也有所减小,SEM下观察有很强的立体感.作者认为合金高温淬火后仍为两相组织,而非单一均匀相,主要与热处理温度和材料的固态相变温度相距较近有关.     

激光熔覆用高硬度铁基合金的研究与应用

研究了激光熔覆Fe-Ni-Cr—B—Si合金粉末时粉末中的碳含量对于熔覆层组织、开裂敏感性、硬度和硬度均匀性的影响。结果表明，粉末含碳量的微小变化能显著改变熔覆层的组织和性能；在相同工艺条件下，粉末含碳量在一定范围内可显著提高熔覆层的硬度、降低熔覆层开裂敏感性，从而获得高硬度无裂纹的熔覆层；碳含量的增加可提高熔覆层的硬度均匀性。本文还报道了用自制Fe基合金粉末成功修复大型轧辊的实例。     

Gold and Gold Alloy foams

The possibilities to manufacture gold-based foams are explored. Gold powder and various powdered alloying elements are mixed with a small volume fraction of a gas-releasing blowing agent. The blend is compacted to a dense precursor, which is then melted in a further step in order to trigger foam formation. We find that gold-silicon alloys containing 2–3 wt.% of silicon or around 8 wt.% of germanium can be foamed using TiH₂ or ZrH₂ as a blowing agent. Foams with about 85% porosity are obtained.     

Effect of Thermal Treatment on the Hardness of Low Gold Content Dental Casting Ag-Pd Alloy

The age-hardening behavior and the mechanism of an experimental low gold content casting Ag-Pd alloy were studied by means of hardness test, XRD, SEM and EPMA, The results show that the hardness of specimens isothermal-aged at 400 oC after solution treated at 900 oC for 30 min increases unidirectionally from 1540 MPa to 3160 MPa with the prolongation of time. However, the hardness of the specimens isothermal-aged at 600 oC after solution treated at 900 oC for 30 min increases quickly and reaches the maximun 2870 MPa at 2 min aging time. Then the hardness decreases unidirectionally and remains at 1600-1700 MPa from 10 to 50 min aging time. Obvious precipitation takes place in the specimens isothermal-aged at 400 and 600 oC revealed by XRD. By SEM and EPMA, the precipitation particles can be seen in the specimens aged at 600 oC for 2 min after solution treated at 900 oC for 30 min. However, the time-FWMH curve shows that the increase of hardness after isothermal-aging is closely related with coherency stain from phase transformation. It is hard to define whether the phase transformation at 400 oC makes a contribution to the change of hardness     

GH4133B合金精化模锻件的模锻工艺

叙述了精化模锻件的计算机变形模拟结果 ,精化模锻件的主要模锻变形工艺参数以及精化模锻件达到的质量指标。采用本研究工艺完全可以预防模锻件的低倍粗晶     

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 在淬火基体成分计算的基础上，根据某一淬火温度下的奥氏体基体的化学成分，Cr W Mo V合金钢淬火硬度可以近似计算为HRC=α(1+β)/(0.00915α＋0.00527)，其中α为基体中含碳量的平方根，β为合金元素对马氏体强化的修正因子。上述淬火硬度计算公式隐含着洛氏硬度测定和马氏体强化机理的对应关系，对其它钢种也适用。Cr W Mo V高合金钢在高温回火时会出现二次硬化特征，二次硬化的最高回火硬度既与各类型碳化物沉淀的热力学和动力学有关，也与残余奥氏体分解过程有关。依据奥氏体化温度下基体成分，提出基体成分配比碳公式为Cp＝0.011W＋0.02Mo＋0.057Cr＋0.19V，二次硬化的回火硬度的计算公式为Hc=a（1+b）/(00127a＋000267)，其中a为基体碳饱和度，b为碳化物沉淀量的修正因子。     

海水泵阀用新型铸造铜合金的研制

研制了一种海水泵阀用新型铸造铜合金，该合金综合力学性能优良：δb≥550MPa，δ0.2≥280MPa，δ5≥18％；耐海水腐蚀性能优异，在7m／s的天然海水冲刷下，腐蚀率低于0．042mm／a，在3．5m／s的含砂海水冲刷下，腐蚀率为0．144mm/a；与目前推广使用的海水管系材料B1O的腐蚀电位相差较小，电偶腐蚀率为0．0092mm／a，能有效抑制海水管系的电流腐蚀，提高海水泵阀的使用寿命。与国内海水泵阀常用的铜合金相比，该合金具有较高的拉伸强度和屈强比，能承受较高的压力，在深海工程等领域也有广泛的应用前景。     

Hot Deformation Behavior and Hardness of a CoCrFeMnNi High-Entropy Alloy with High Content of Carbon

A CoCrFeMnNi high-entropy alloy with a high content of carbon was synthesized, and its hot deformation behavior was studied at the temperatures 800–1000 ℃ at the strain rates ranging from 0.001 to 0.1 s~(-1).As-prepared alloy is a face-centered cubic-structured solid solution, with a large amount of carbides residing at grain boundaries.True stress–strain curves were employed to develop the constitutive equation of apparent activation energy.The apparent activation energy( Q) was found to be 423 kJ mol~(-1), indicating a dynamic flow softening behavior.The size of dynamic recrystallized(DRXed) grains increases with increasing the temperature or decreasing the strain rate.A processing map was sketched on the basis of the flow stress.The temperature range of 900–1000 ℃ and 10~(-3)–10~(-2.6) s~(-1) strain rate were found to be the optimum hot-forging parameter.With increasing temperature or decreasing strain rate, the volume fraction of fine carbides(≤ 1 μm) increases.A lot of coarse carbides can be found in the matrix after deformation at 800 ℃, which leads to a high hardness value of 345 HV.The carbides after deformation at 1000 ℃ are mainly nano-sized M_7C_3 and M_(23)C_6, which can promote the nucleation of DRX.     

Ni-Cu-P合金显微组织和硬度的研究

熔制的Ｎｉ－Ｃｕ－Ｐ合金显微组织由Ｎｉ－Ｃｕ,Ｃｕ－Ｎｉ两种固溶体枝晶和弥散其中的Ｎｉ３Ｐ组成。随着磷含量的增加,Ｎｉ－Ｃｕ－Ｐ合金的硬度显著提高。热处理对Ｎｉ－Ｃｕ－Ｐ合金的显微组织和硬度无显著影响。     

铁碳合金平衡组织观察及硬度测定

设计试验方案,制备金相试样,将试样进行热处理,用金相显微镜观察记录显微组织,并选定洛氏硬度作为硬度测试参数,对热处理前后的金相组织进行观察、硬度的测定。     

合金铸铁光束熔凝处理后的组织和硬度

采用自研的ＳＲ－Ⅱ型５ｋＷ聚焦光束加热设备对珠光体合金铸件进行了表面熔凝强化处理。借助扫描电镜、光学显微镜、显微硬度和表面硬度计研究了采用不同聚焦模式的光束熔凝处理的合金铸铁的表面硬度、显微硬度分布及光束热作用区的组织转变特点。结果表明,当采用单一模式的反光镜聚焦时,功率密度较低、热作用区的奥氏体发生了托氏体－索氏体转变;而采用透镜与反光镜配合的复式聚焦模式时,由于功率密度的提高,奥氏体转变为马氏     

The Control and Characteristics of Acid Alloy Gold Used as a Decorative Plate

Brief comparison has been made between the alkaline cyanide and acid citrate gold plating baths. Operating conditions of a proprietary acid bath and their effect on cathode efficiency have been investigated. The low gold and nickel metal content generally adopted in these baths and the marked effect of slight variation in these metals on the characteristics of the deposit and trouble-free running of the process make regular analytical control important, as this affects economy of process and quality of product. Brief mention has been made of the application of atomic absorption spectrophotometry as a convenient means of analytical control. Plating distribution can be greatly improved by careful consideration of anode configuration and cathode jig design. The most suitable anode material was found to be gold strip, or as an alternative, platinized expanded titanium mesh. In the proprietary acid bath under consideration, carbon or stainless steel anodes were found to be unsuitable.     

银电铸金饰品的成分和硬度测定

采用硝酸溶解分银-重量法测定了银电铸金饰品中的金量,差减法得到银量;测定了饰品的维氏硬度。批量样品测定的统计表明,大部分送检饰品中金、银的含量和纯度符合饰品质量要求,电镀条件控制不当可能是少量饰品金含量或纯度不足的原因。在硬度检测中,采用景深法,引入不规则曲面偏差的修正系数,批量结果表明,银电铸金饰品的表面维氏硬度为100~145HV0.1。     

FeCoNiCuMox多主元合金的组织与硬度研究

采用X射线衍射、扫描电镜和硬度测试等方法,研究了Mo含量对FeCoNiCuMox多主元合金微观组织和硬度的影响.结果表明,合金由简单的FCC相和BCC相组成,随Mo含量的增多,FCC相含量减少,BCC相含量增多,共晶组织的含量增加,硬度逐渐增大,当x=1时,FeCoNiCuMo合金的硬度值为478 HV.     

YG30硬质合金与因瓦合金TIG焊接头的组织与硬度的分析研究

本文选用不同厚度的Ni-Fe、Ni-Fe-C-Mn-Nb因瓦合金,与YG30在不加填充材料、对接条件下直接进行TIG焊接试验,运用光学显微镜、扫描电镜、显微硬度仪等对焊接接头的显微组织和硬度进行研究分析。结果表明,Ni-Fe因瓦合金与YG30连接,在YG30/因瓦合金焊接接头界面区硬质合金侧形成η-碳化物;Ni-Fe-C-Mn-Nb因瓦合金与YG30连接,在界面区没有η-碳化物形成。不同厚度、不同工艺参数的焊接接头中,厚度为2mm、电流为135A和厚度为4mm、电流为145A的两种焊接接头组织均匀,界面冶金结合良好,硬度分布过渡平缓。     

淬火温度对Fe-B-C铸造合金显微组织和硬度的影响

在水冷淬火条件下,研究了淬火温度对含0.4%C和2.0%B的Fe-B-C铸造合金显微组织和宏观硬度的影响。结果表明,Fe-B-C铸造合金在淬火加热过程中发生奥氏体化。淬火温度低于900℃时,Fe-B-C铸造合金淬火组织由马氏体和少量珠光体组成。超过1050℃后,淬火组织粗大,且出现低硬度奥氏体。Fe-B-C铸造合金在900~1050℃淬火后,都可获得马氏体+硼化物组成的复合组织,硬度大于55 HRC。用这种材料制造的破碎机锤头,使用寿命达到高锰钢的2~3倍。     

材料涂层(合金层)硬度的测量方法与技巧

介绍了活塞、活塞环、轴瓦涂层硬度的试样制备过程及注意要点,强调正确制备试样是测量涂层硬度的基础。分析了维氏硬度测量误差的来源,指出试验载荷选择遵循的原则,并分别就轴瓦涂层硬度、活塞环涂层硬度、活塞涂层硬度的测量方法进行了讨论,说明正确选择涂层硬度的测量方法至关重要。     

AlCuCrFeNiMn高熵合金组织及硬度的研究

利用真空电弧炉熔铸等摩尔比的AlCuCrFeNiMn多主元高熵合金。扫描电镜及能谱分析表明,合金的铸态组织是典型的树枝晶,铜偏聚于枝晶间。晶间分布着大量微小颗粒,有的颗粒尺寸甚至达到纳米级。AlCuCrFeNiMn高熵合金具有高硬度与耐回火软化特性,铸态硬度为380HBW,600℃退火2h后硬度为376HBW。