共查询到19条相似文献,搜索用时 157 毫秒
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采用机械合金化法制备出Mo-8wt%Cu超细复合粉末,并对由该复合粉末所制得的压坯进行了液相烧结,利用SEM、XRD等分析手段对复合粉末的特性和烧结体的组织进行了表征和观察,实验结果表明,该方法制备的Mo-8wt%Cu超细复合粉末颗粒细小,平均粒径在300nm左右,高能球磨后的复合粉末由Mo-Cu过饱和固溶体相和Cu相组成,而且两相的晶粒度达到纳米级,其中Mo-Cu过饱和固溶体相的晶粒约为106nm,复合粉末具有很高的烧结特性,经高温烧结后合金致密度达到98.5%以上,而且金相组织分布均匀。 相似文献
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纳米晶钨基重合金粉末的注射成型与固相烧浇 总被引:8,自引:0,他引:8
采用高能球磨技术制备了90W-7Ni-3Fe(质量分数,%)纳米晶钨基重合金粉末,研究了该粉末的注射成型和烧结行为,并与传统混合粉末进行了比较.结果表明,机械球磨可以有效地增加粉末喂料的固体粉末含量,改善粉末料的均匀性,并可促进固相烧结的致密化.纳米粉末注射成形坯在1300~1450℃进行固相烧结后,可得到近全致密(>99%),晶粒细(3~5μm)、拉伸强度高(≥1130MPa)和几乎无变形的重合金样品. 相似文献
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W-35%Cu粉末形变强化复合材料组织及性能研究 总被引:2,自引:0,他引:2
为了提高W-Cu复合材料的致密度,采用机械球磨-冷压制坯-液相烧结-热静液挤压-热处理工艺,制备出微观组织弥散分布、性能优异的W-35%Cu复合材料.采用扫描电镜、电子探针等测试手段分别对烧结及挤压后材料的组织及性能进行了分析.实验结果表明,采用机械球磨技术制备的W-35%Cu复合粉,经液相活化烧结后,再经热静液挤压进一步形变和致密,材料的硬度以及导电性能都有较大提高.在800℃真空热处理2 h后,获得了硬度高于200HB,电导率高于40m/Ω·mm2的W-35%Cu形变复合材料. 相似文献
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综述了热静液挤压技术在烧结态粉末冶金难变形材料挤压成形与粉末体高致密化固结方面的研究进展。简述了热静液挤压工艺原理、工艺特点与适用范围,分析了热静液挤压润滑层形成的影响因素,介绍了热静液挤压润滑介质研制和热静液挤压技术在粉末冶金高比重钨合金、γ-TiAl基合金材料的挤压成形以及纳米晶铝合金、弥散强化铜合金、NdFeB永磁合金等金属粉末体材料的高致密化固结成形方面的应用,指出了热静液挤压工艺的技术优势与发展前景。 相似文献
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纳米晶钨基重合金粉末的注射成型与固相烧结 总被引:7,自引:0,他引:7
采用高能球磨技术制备了90W-7Ni-3Fe(质量分数,%)纳米晶钨基重合金粉末,研究了该粉末的注射成型和烧结行为,并与传统混合粉末进行了比较,结果表明,机械球磨可以有效地增加粉末喂料的固体粉末含量,改善粉末料的均匀性,并可促进团相烧结的致密化,纳米粉末注射成形坯在 1300~1450℃进行固相烧结后,可得到近全致密(>99%)、晶粒细(3~5μm)、拉伸强度高(≥1130MPa)和几乎无变形的重合金样品 相似文献
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将TiH2、Al-V粉末压制成型后进行真空烧结,制备出Ti6Al4V(TC4)合金,使用XRD、金相和SEM断口形貌观测以及力学性能测试等手段对其表征,研究了烧结温度对合金力学性能的影响。结果表明:烧结样品由密排六方α-Ti和体心立方β-Ti双相组成,其形貌呈等轴、网篮或板条(片状、针状)状,随着烧结温度的提高和保温时间的延长等轴组织减少,片状组织和针状组织增加且其组织粗化,在1150℃烧结的样品具有较好网篮结构组织;用该方法可制备相对密度为96.9%~99.6%、抗拉强度为719.3~914.1 MPa、延伸率为6.2%~9.4%、硬度为313.2~364.8HV的TC4合金试样;在1150℃保温1.5 h的样品性能较好,其抗拉强度最高(914.1 MPa),对应的延伸率和硬度分别为7.6%和355.5HV;用纯TiH2粉末烧结样品的断口呈韧性断裂;加入合金元素的样品其断口逐渐由韧性断口变为韧性和脆性混合的断口,其强度提高、延伸率下降。 相似文献
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为了制备高力学性能细晶Mg-6Al合金坯料,采用金相显微镜、材料拉伸实验机等手段对Mg-6Al合金铸坯进行等径道角挤压实验研究.并利用热处理工艺对挤压后材料进行处理,研究热处理工艺参数对材料力学性能的影响规律.结果表明,Mg-6Al合金的铸坯的抗拉强度为196.4MPa,延伸率为12.6%.经过等径道角挤压的Mg-6Al合金坯料的晶粒被大大细化,其晶粒尺寸由铸坯的140μm左右细化到8μm左右.其力学性能有很大提高,抗拉强度由196.4MPa提高到308.2MPa;延伸率由12.6%提高到30.6%.等径道角挤压工艺是一种非常好的制备高力学性能、细晶Mg-6Al合金的工艺方法.固溶和人工时效热处理工艺对等径道角挤压的Mg-6Al合金坯料的强度有较大影响,对延伸率影响较小. 相似文献
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The Mg-12Gd-3Y-0.6Zr (wt. %) alloy was subjected to conventional and hydrostatic extrusion in two subsequent steps. The best combination of mechanical properties (strength and ductility) was achieved by RT hydrostatic extrusion following conventional extrusion at 430 °C, with the ultimate tensile strength (UTS), tensile yield strength (TYS) and elongation being 485 MPa, 413 MPa and 5.2% at room temperature. The texture results of extruded rods indicate that the c-axis of most grains was aligned preferentially perpendicular to the extrusion direction, forming a typical extrusion Mg fiber texture. 相似文献
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Microstructure and mechanical properties of as-cast and as-extruded Al–Si–Mg alloys with different Si content are investigated by tensile test, microstructure observation. High density of Si particles in the Al alloys can induce dynamic recrystallization during hot extrusion and it becomes more matured with an increase in the density of Si particles. The tensile strength of as-cast and as-extruded alloys can be improved with the increase of Si content and hot extrusion make the elongation of alloys increase dramatically. Considerable grain refining effect caused by recrystallization occurred during hot extrusion of S2 (equivalently commercial A356 alloy) and S3 (near eutectic alloy) alloys plays an important role in the improvement of elongation. A good combination of strength and elongation for the as-extruded S3 alloy indicates that near eutectic Al–Si alloys can be hot-extruded to produce aluminum profiles with high performance. 相似文献
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采用机械合金化制备Mo-18Cu复合材料,利用SEM、XRD和万能试验机研究了Co含量对Mo-18Cu合金的相对密度、力学性能、断口形貌组织、导热和导电性能的影响。试验结果表明,活化元素Co的添加降低了Mo-18Cu合金的烧结致密化温度100℃,增加了合金的相对密度、抗弯强度及硬度,但导电和导热性能降低。含Co 2.0wt%Mo-18Cu合金在1250℃烧结2h获得较好的综合性能,合金的相对密度、抗弯强度、硬度、电阻率和热导率分别为99.1%,960 MPa,69 HRA,2.06×10-7Ωm和142 W.m-1.K-1。显微组织为均匀细小的网络结构。 相似文献
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The microstructure, texture and mechanical properties of AA7003 extrusion sheets processed with different parameters were investigated. Furthermore, the effects of the microstructure and texture on the mechanical properties were discussed. The grain morphology and the texture were analyzed by using a combination of scanning electron microscopy and electron backscatter diffraction. Moreover, the mechanical properties were measured by tensile tests and the tensile fracture morphology was also analyzed by scanning electron microscopy. The results showed that the maximum recrystallization extent occurred at the extrusion process conditions of T = 450 °C and v = 1 mm/s, and the increase in recrystallization extent had a negative effect on the tensile strength. Moreover, a relatively strong recrystallization cube orientation <100> existed when the extrusion temperature was 470 °C, showing a high tensile strength and elongation. Thus, it can be concluded that the cube texture is beneficial to the tensile strength and elongation in extruded AA7003 alloy. 相似文献
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Improvement of Ductility of Powder Metallurgy Titanium Alloys by Addition of Rare Earth Element 总被引:1,自引:0,他引:1
Yong LIU Lifang CHEN Weifeng WEI Huiping TANG Bin LIU Baiyun HUANG 《材料科学技术学报》2006,22(4):465-469
Ti-4.5Al-6.0Mo-1.5Fe, Ti-6Al-1Mo-1Fe and Ti-6Al-4V alloys were prepared by blended elemental powder metallurgy (PM) process, and the effects of Nd on the microstructures and mechanical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It was found out that the addition of Nd increased the density of sintered titanium alloys slightly by a maximum increment of 1% because small amount of liquid phase occurred during sintering. The addition of Nd shows little effect on the improvement of tensile strength, while the elongation is significantly improved. For example, the elongation of Ti-4.SAl-6.0Mo-1.5Fe can be increased from 1% without addition of Nd to 13% at a Nd content of 1.2 wt pct. 相似文献
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为了提高镁合金的耐热性能,在Mg-Zn合金中加入Si,形成Mg-Zn-Si镁合金.采用ECAP工艺在变形温度为573 K和挤压路径为Bc条件下对Mg-Zn-Si镁合金进行不同道次的变形.运用金相显微镜(OM)、X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等手段对变形后的Mg-Zn-Si镁合金进行了组织表征,对变形后的合金进行了室温拉伸和高温蠕变等力学性能测试.结果表明:随着挤压道次增加,α-Mg基体、Mg Zn相及Mg2Si相均得到细化且分布趋于均匀.1道次挤压后部分基体α-Mg细化,4道次挤压后α-Mg的尺寸减小为5~10μm,且晶粒大小趋于均匀;2道次挤压后Mg2Si相枝晶在原位置破碎为颗粒状,6、8道次挤压后Mg_2Si相呈弥散分布.4道次挤压后合金的屈服强度和抗拉强度均提高120%,伸长率提高353%;8道次挤压后合金的抗拉强度和伸长率与4道次相比变化不大,但屈服强度进一步提高了19%.随着挤压道次增加,高温抗蠕变性能提高,8道次后高温稳态蠕变速率降低5倍.Mg2Si相细化机理为受剪切而机械碎断. 相似文献