稀土对WC—8Ni硬质合金性能影响的研究

研究了添加微量稀土氧化物对ＷＣ－８Ｎｉ硬质合金物理机械性能的影响。在用Ｘ射线衍射、扫描电镜及透射电镜等手段对含稀土ＷＣ－８Ｎｉ合金进行显微结构分析的基础上，探讨了稀土在合金中的分布状态、对组织结构的影响及其强化机理。并指出，通过添加微量稀土氧化物，可使ＷＣ－８Ｎｉ硬质合金的物理机械性能接近和达到ＹＧ８的水平。     

钇在钴基合金和硬质合金中的作用

对钴基合金和ＹＧ８Ｒ硬质合金进行了Ｘ射线衍射、ＳＥＭ、ＴＥＭ和ＥＤＳ的观察和分析。结果表明：稀土的加入对钴相的晶格参数没有影响，但使钴相的粒度显著变小，并使合金中ＷＣ相晶粒尺寸的不均匀和分布的不均匀得到明显改善；在Ｃｏ基（Ｃｏ－ＷＣ－Ｙ）合金中可形成的稀土相有稀土氧化物Ｙ２ＷＯ６和稀土金属经物Ｃｏ５Ｙ８和Ｃｏ２Ｙ。     

稀土元素对WC－Ni硬质合金性能的影响

研究了稀土元素对Ｎｉ代Ｃｏ硬质合金性能的影响。结果表明，稀土元素可使ＷＣ－８％Ｎｉ硬质合金的性能大大提高，因而使其可以在许多领域取代传统的ＷＣ－Ｃｏ硬质合金。     

稀土元素对WC—Ni硬质合金性能的影响

研究了稀土元素对Ｎｉ代Ｃｏ硬质合金性能的影响，结果表明，稀土元素可使ＷＣ－８％Ｎｉ硬质合金的性能大大提高，因而使其可以在许多领域取代传统的ＷＣ－Ｃｏ硬质合金。     

WC—Ni硬质合金研究

本文叙述了以Ｎｉ替代Ｃｏ作硬质合金粘接剂，通过在Ｎｉ中添加适量的金属添加剂，来提高和改善ＷＣ－Ｎｉ硬质合金性能，采用此方法生产的ＷＣ－Ｎｉ硬质合金的机械性能和使用性能完全可以达到ＷＣ－Ｃｏ硬质合金的水平。     

少量A1对WC－13％Fe／Co／Ni硬质合金性能和组织的影响

以ＷＣ－１３％Ｆｅ／Ｃｏ／Ｎｉ合金作为基体合金，添加少量Ａ１以研究其对ＷＣ－１３％Ｆｅ／Ｃｏ／Ｎｉ硬质合金的性能和组织的影响。结果发现：Ａ１可以细化合金中的ＷＣ晶粒，并在提高合金硬度的同时，使其抗弯强度提高１００～２００ＭＰａ。金相研究表明，添加Ａ１的ＷＣ－１３％Ｆｅ／Ｃｏ／Ｎｉ合金中的粘结相主要是γ相和板条马氏体，局部有α＋（Ｆ，Ｍｅ）＿３Ｃ的片层状组织存在。     

少量Al对WC—13?／Co／Ni硬质合金性能的组织的影响

以ＷＣ－１３％Ｆｅ／Ｃｏ／Ｎｉ合金作为基体合金，添加少量Ａｌ以研究其对ＷＣ－１３％Ｆｅ／Ｃｏ／Ｎｉ硬质合金的性能和组织的影响，结果发现，Ａｌ可以细化合金中的ＷＣ晶粒，并在提高合金硬度的同时，使其抗弯强度提高１００～２００ＭＰａ，金相研究表明，添加Ａｌ的ＷＣ－１３％Ｆｅ／Ｃｏ／Ｎｉ合金中的粘结相主要是γ相和板条马氏体，局部有α＋（Ｆｅ，Ｍｅ）３Ｃ的片层状组织存在。     

国外WC－Co硬质合金中钴的替代研究概况

介绍了国外ＷＣ－Ｎｉ，ＷＣ－Ｃｏ－Ｎｉ及ＷＣ－Ｆｅ－Ｃｏ－Ｎｉ等系列新型粘结剂硬质合金以及ＷＣ－Ｆｅ、ＷＣ－Ｆｅ－Ｃｏ及ＷＣ－Ｆｅ－Ｎｉ等硬质合金的研究情况，并对以铁、镍代钴的硬质合金研制特点及今后的发展方向进行了分析。     

国外WC—Co硬质合金中钴的替代研究概况

介绍了国外ＷＣ－Ｎｉ，ＷＣ－Ｃｏ－Ｎｉ及ＷＣ－Ｆｅ－Ｃｏ－Ｎｉ等系列新型粘结剂硬质合金以及ＷＣ－Ｆｅ，ＷＣ－Ｆｅ－Ｃｏ及ＷＣ－Ｆｅ－Ｎｉ等硬质合金的研究情况，并对以铁，镍代钴的硬质合金研制特点及以今后的发展方向进行了分析。     

预弥散强化镍粉——硬质合金的新型粘结剂

叙述了以预弥散有纳米Ａｌ２Ｏ３的镍粉代替钴粉作粘结剂以提高ＷＣＮｉ硬质合金性能方面的初步研究；制得的ＷＣＮｉ硬质合金的物理机械性能可达到ＷＣＣｏ合金的水平     

Improving Wear Resistance of the Ni-base Thermal Spray-Welding Coating Using Rare Earths

ＩｍｐｒｏｖｉｎｇＷｅａｒＲｅｓｉｓｔａｎｃｅｏｆｔｈｅＮｉｂａｓｅＴｈｅｒｍａｌＳｐｒａｙＷｅｌｄｉｎｇＣｏａｔｉｎｇＵｓｉｎｇＲａｒｅＥａｒｔｈｓＺｈａｉＧｕａｎｇｊｉｅ（翟光杰）（ＩｎｓｔｉｔｕｔｅｏｆＰｈｙｓｉｃｓ，ＡｃａｄｅｍｉｃａＳｉ...     

Mechanical properties of the A356 aluminum alloy modified with La/Ce

The research of rare earths for the synthesis of materials with improved mechanical performance is of great interest when they are considered for potential applications in the automotive industry. In this regard, the effect on the mechanical properties and microstructure of the automotive A356 aluminum alloy reinforced with 0.2 (wt.%) Al-6Ce-3La (ACL) was investigated. The ACL was added to the melted A356 alloy in the as-received condition and processed by mechanical milling. In the second route, the effect of the ACL processed by mechanical milling and powder metallurgy techniques was investigated, and compared with the results obtained from the A356 alloy strengthened with ACL in the as-received condition. Microstructural properties were evaluated by means of X-ray diffraction in order to observe the solubility of Ce/La in the Al matrix. In addition, electron microscopy was employed in order to investigate the effect of milling time on the size and morphology of La/Ce phase under milling process. Mechanical properties of the A356 alloy modified with ACL were measured by hardness and tensile test. For comparison unmodified specimens of the A356 were characterized according to the previous procedure. The microstructural and mechanical characterization was carried out in specimens after solution and artificial aging. Observations in scanning electron microscopy indicated a homogeneous dispersion of La/Ce phases by using both routes; however, mechanical results, in the modified A356 alloy with the ACL in the as-received condition, showed an improvement in the mechanical performance of the A356 alloy over that reinforced with the ACL mechanically milled.     

Y2O3对WC—8Ni硬质合金性能和烧结温度的影响

研究了添加Ni质量1．1％的Y2O3对WC－8Ni硬质合金的物理化学机械性能及其烧结温度的影响。发现稀土Y2O3的加入不仅提高了合金的性能，而且降低了烧结温度。利用扫描电镜等分析手段对三种烧结温度的硬质合金进行了显微分析比较，探讨了WC－8Ni合金性能与烧结温度的关系及Y2O3降低烧结温度的原因。     

混合稀土变质高硅铝活塞合金

采用镧铈钇型混合稀土对过共晶Al—24％Si活塞合金进行了变质处理，对其金相组织和力学性能进行了研究。结果表明：与单一稀土铈变质相比较，镧铈钇型混合稀土对该合金具有较好的变质效果，初晶硅的尺寸基本保持在20μm左右，且尖角大多钝化呈团球化状，共晶硅呈短杆状均匀分布；合金经过混合稀土变质后，晶界处产生复杂化合物组织起到了弥散强化作用，使其综合力学性能明显提高，尤其是高温强度的显著提高，已完全满足活塞合金在使用性能上对高温强度的要求。     

Binder deformation in WC-(Co,Ni) cemented carbide composites

The microstructural responses to monotonic and cyclic compressive loading of three WC-(Co,Ni) alloys have been characterized and measured by high voltage transmission electron microscopy and neutron diffraction. A base alloy comprising WC-17 wt pct Co was prepared and evaluated, along with two alloys in which the binder composition was altered by replacing 15 pct and 30 pct of the total cobalt by nickel. Results are presented for strains of 0, 0.75, and 5.0 pct, and for two fatigue stress levels, both at 0.5 million cycles. Predominant binder-deformation mechanisms were observed to shift with increasing Ni content from the fcc-hcp martensitic transformation to slip plus twinning over the composition range studied. In the base alloy, 44.5 vol pct of the binder had transformed at the highest strain level, while only 11.4 pct transformation occurred at the same strain in the 30 pct Ni-binder alloy. The shift in binder plasticity mechanisms and the corresponding changes in composite stressstrain behavior have been discussed with respect to several theories on the role of binder deformation in cermet mechanical response. Formerly Graduate Research Assistant, University of Missouri, Columbia, MO     

Ni元素对Al-Cu-Mn合金组织及力学性能的影响

为研究添加Ni元素对Al-5.0Cu-0.6Mn合金组织及力学性能的影响,通过硬度试验、拉伸力学试验及摩擦磨损试验对合金力学性能进行研究;采用扫描电子显微镜、激光共聚焦显微镜及透射电子显微镜对合金微观组织进行检测分析。结果表明：向Al-5.0Cu-0.6Mn合金中添加Ni元素后,由于Al₃CuNi相析出的强化作用,并且与基体结合良好的增强相颗粒能均匀分布于合金中,使得合金硬度和强度大幅提高,摩擦磨损深度显著降低,综合力学性能得到有效的提升。当Ni元素的添加量为0.3%(质量分数)时,由于T相(Al₂₀Cu₂Mn₃)和Al₃CuNi相分布比较均匀,合金综合性能较为理想,其HV硬度、抗拉强度、摩擦磨损系数分别为126.4 MPa、395.2 MPa、0.12。     

Effects of Rare Earth Elements on Properties and Structure of WC－14TiC－8Co Cemented Carbide

ＥｆｆｅｃｔｓｏｆＲａｒｅＥａｒｔｈＥｌｅｍｅｎｔｓｏｎＰｒｏｐｅｒｔｉｅｓａｎｄＳｔｒｕｃｔｕｒｅｏｆＷＣ－１４ＴｉＣ－８ＣｏＣｅｍｅｎｔｅｄＣａｒｂｉｄｅＨｅＣｏｎｇ－Ｘｕｎ；（贺从训）；ＷａｎｇＹｏｕ－Ｍｉｎｇ；（汪有明）；ＬｉｎＣｈｅｎ－Ｇｕ...     

Al-2.3Cu-1.7Mg-1.2Fe-1.2Ni合金的时效行为研究

采用硬度测试、电导率测试、常温力学性能测试等方法研究了单级时效处理过程中时效温度和时效时间对Al-2.3Cu-1.7Mg-1.2Fe-1.2Ni合金力学性能和电导率的影响规律,并利用金相显微镜(OM)、扫描电镜(SEM)、透射电镜(TEM)、选区电子衍射(SAED)等手段对合金淬火态以及几种不同时效处理制度下的显微组织进行了研究.结果表明,合金经固溶淬火处理后仍残留有较多的大尺寸第二相,淬火态组织存在的第二相主要有Al9FeNi,Al7 Cu2 Fe,Al7 Cu4 Ni等.单级时效处理过程中,时效处理的温度越高,达到峰时效所需的时间越短,材料的峰时效硬度值越低;电导率随时效时间的延长而不断上升,时效温度越高,电导率的增长速率越快.峰时效条件下合金内主要沉淀强化相包括S’相和S"相,晶界上有明显的链状析出物存在,呈不连续分布;峰时效条件下,合金棒材的极限抗拉强度、屈服强度和延伸率分别为455 MPa,391 MPa和10.6％,电导率可达到21.6 MS·m-1.     

粘结剂成分对WC－20（Fe／Co／Ni）硬质合金力学性能和显微组织的影响

用常规的粉末冶金工艺试制了四种成分的ＷＣ－２０（Ｆｅ／Ｃｏ／Ｎｉ）合金，优选粘结剂的成分及总碳量可使其力学性能最佳。着重研究了ＷＣ－２０（Ｆｅ／Ｃｏ／Ｎｉ）合金的力学性能和显微组织，发现：粘结相为李晶马氏体和奥氏体时，其主要力学性能不低于ＷＣ－２Ｃｏ；而粘结相全部为板条马氏体时，其主要力学性能低于ＷＣ－２Ｃｏ     

Effects of Rare Earths on Properties and Microstructure of Automotive Friction Materials

Rare earth compounds as modifiers used widely in modern friction materials can enhance the interracial binding of constituents of materials and improve the comprehensive properties of materials evidently. However, there are still few reports on application of rare earth in automotive friction materials. In order to study the effect mechanism of rare earths in friction materials, a rare earth compound was selected as additive and the effects of materials doped with or without rare earth on friction and wear properties of materials were studied. The microstructure and worn surface morphology were observed by scanning electron microscopy and the macro performance was discussed. Worn surface element constitution of materials was analyzed by energy dispersive spectroscopy. Effect mechanism of rare earths on friction and wear behaviors of friction materials were discussed. The results show that doping rare earths in friction materials can stabilize friction Coefficient, lower the wear rate of materials and increase the impact strength of materials. The flexibility and fracture resistance of materials is greatly improved. Worn surface of materials doped with rare earth is compact and the surface adhesion is greatly enhanced.