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1.
镁合金半固态材料成形与浆料制备工艺研究   总被引:9,自引:1,他引:9  
由一对带有螺纹的内外桶的旋转,在其间的缝隙形成剧烈的剪切应力场的作用原理自行研制的镁合金浆料制备装置。内外桶缝隙控制在1~3mm。通过控制桶的转速可以获得0~100s^-1剪切速率,剪切时的温度在50~900℃之间任意调节。通过计算分析:AZ91合金的半固态流变成形温度区间为550~590℃,同时得到了,AZ91合金的固相体积分数fs(固相率)随温度变化的关系曲线。此外还确定了转速与剪切速率的关系。在温度为570℃,固相体积分数为0.41时,不同的剪切速率条件下镁合金浆料制备与压铸的实验结果表明:利用该装置制备出的半固态浆料晶粒圆整,组织均匀,并随着剪切速率的提高固相颗粒更加细小均匀。  相似文献   

2.
钢铁半固态成形技术的研究进展和展望   总被引:2,自引:0,他引:2  
低熔点合金半固态成形技术被专家称为21世纪新兴的金属制造关键技术。该技术已经成功地在商业领域中运行,人们一直在探索将此技术应用于钢铁材料。本文综述了钢铁半固态成形技术的研究开发过程,介绍了钢铁半固态成形的工艺、浆料的制备方法、半固态金属的微观组织演变以及对这种成形工艺的展望。笔者认为电磁搅拌制备浆料方法中的搅拌是无接触搅拌,更适用于高熔点钢铁材料。由于触变成形工艺本身的特点,使其更适宜于钢铁等高熔点材料的半固态成形控制。  相似文献   

3.
60Si2Mn弹簧钢半固态浆料的制备研究   总被引:2,自引:0,他引:2  
研究了60Si2Mn弹簧钢半固态浆料的制备规律,结果表明:在本实验条件下,当搅拌时间为2min时,可以获得尺寸大小为100-300μm、固相率为40%~50%的球状初生奥氏体的半固态浆料,这样的半固态浆料便于从搅拌室底孔中放出;电磁搅拌使60Si2Mn弹簧钢熔体获得均匀的温度场和溶质场,抑制了发达的初生奥氏体枝晶的形成,为球状晶的获得奠定了基础;电磁搅拌引起蔷薇状初生奥氏体枝晶出现强烈的温度起伏和枝晶臂根部熔断是获得球状晶粒最重要的原因。  相似文献   

4.
本文详细论述了半固态非枝晶组织合金制备技术的基本原理与特点,介绍了半固态非枝晶组织合金制备技术的现状与发展概况,并展望了半固态非枝晶组织合金的应用前景。  相似文献   

5.
金属半固态铸造成形技术   总被引:2,自引:0,他引:2  
金属的半固态铸造是近年来出现的一种新的铸造加工成形方法。该方法与传统的全液态铸造相比,具有节约能源、生产率高、产品质量好等优点。本文介绍了半固态金属浆料的制备方法,半固态压铸、半固态连铸等金属半固态铸造成形技术,并指出了存在的问题及进一步研究工作。  相似文献   

6.
采用立弯式浇道制备A356铝合金半固态浆料,研究了浇注温度对A356铝合金半固态浆料组织的影响,并考察了浆料经过均热处理后的组织。结果表明,采用立弯式浇道可以制备出半固态浆料,在本实验条件下,获得理想的半固态A356铝合金浆料的浇注温度为630℃和640℃,而且随着浇注温度的降低,初生相的形态由树枝状→蔷薇状→颗粒状转变;经过感应均热后,初生相更圆整,且尺寸、分布都很均匀。  相似文献   

7.
利用Al-La稀土中间合金对液态A356铝合金进行了细化处理,并用低过热度浇注技术制备了半固态A356铝合金浆料,研究了稀土La对所制备半固态A356铝合金的初生α相形貌和尺寸的影响.研究结果表明,舍有适量稀土La的A356铝合金经低过热度浇注可制备具有颗粒状和蔷薇状初生α相的半固态浆料,稀土La可显著改善半固态A35...  相似文献   

8.
半固态铸造是一种新的材料成形技术,综述了半固态铸造合金的组织变化,坯料制备,充型过程数值模拟和应用等方面的研究成果,同时对我国发展半固态铸造技术得出了若干值得重视的问题。  相似文献   

9.
介绍了一种实验室自主研发的轻合金半固态浆料制备设备——锥桶式流变成形机(TBR),该设备利用刻有凸纹和沟槽的内、外锥桶的相对转动,使合金熔体在凝固过程中受到剧烈的剪切搅拌,从而获得合金半固态浆料.对TBR工艺的传热模型进行了推导,以A356为实验材料得出制备的A356铝合金半固态浆料温度与浇注温度的关系式,同时分析了不同浇注温度下合金熔体的冷却规律和获得的半固态组织形貌.结果表明,适当降低A356合金熔体的浇注温度可以延长初生固相受到的剪切时间和增加剪切次数,从而获得细小、均匀的半固态组织.当浇注温度为640℃时,初生固相平均晶粒尺寸为68μm,形状因子为0.82.  相似文献   

10.
利用Al-La稀土中间合金对液态A356铝合金进行了细化处理,并用低过热度浇注技术制备了半固态A356铝合金浆料,研究了稀土La对所制备半固态A356铝合金的初生α相形貌和尺寸的影响.研究结果表明,含有适量稀土La的A356铝合金经低过热度浇注可制备具有颗粒状和蔷薇状初生α相的半固态浆料,稀土La可显著改善半固态A356铝合金中初生α相的晶粒尺寸和颗粒形貌.稀土La对半固态A356铝合金的初生α相细化机理可能与稀土在铝合金中诱发的共晶反应有关.  相似文献   

11.
介绍了采用现场制浆、就地燃烧的一条龙水煤浆应用技术,在30t/h的轧钢加热炉上连续燃烧应用3年时间表明,在节能、环保、经济效益和社会效益等方面都有很好的效果。  相似文献   

12.
半固态浆料液相的凝固行为决定了其二次凝固组织,这将直接影响半固态成形件的性能.Mg-Al系镁合金随着成分、凝固行为的不同,其二次凝固组织有较大的不同.该文描述了Mg-Al系合金半固态浆料液相凝固过程以及二次凝固组织特征,并针对其特征对其形成原因展开了分析.  相似文献   

13.
樊刚  程钢  张家涛 《云南冶金》2002,31(4):38-41
叙述了半固态金属的流变学理论,常规铸造组织和半固态金属的流变行为,固相体积分数,剪切速率,冷却速度等因素对半固态金属表观粘度的影响,以及半固态成形技术的研究现状,以期推动半固态流变理论的研究和半固态加工技术的实际应用。  相似文献   

14.
The microstructure of 1.4?% carbon steel produced either by ordinary casting or semi-solid casting with different primary fraction of solids using cooling plate technique was investigated. The microstructure of ordinary ultrahigh-carbon steel (O-UHCS), was improved by the semi-solid processing. Grain boundary cementite thickness of UHCS and its morphology is affected by semi-solid process. Grain boundary cementite thickness of about 2???m can be achieved by pouring the semi-solid slurry with 0.31 fraction of solid. The pearlitic interlamellar spacing of semi-solid processed UHCS is shorter compared to O-UHCS.  相似文献   

15.

Multi-axial compression of the mushy zone occurs in various pressurized casting processes. Here, we present a drained triaxial compression apparatus for semi-solid alloys that allow liquid to be drawn into or expelled from the sample in response to isotropic or triaxial compression. The rig is used to measure the pressure-dependent flow stress and volumetric response during isothermal triaxial compression of globular semi-solid Al-15 wt pct Cu at 70 to 85 vol pct solid. Analysis of the stress paths and the stress–volume data show that the combination of the solid fraction and mean effective pressure determines whether the material undergoes shear-induced dilation or contraction. The results are compared with the critical state soil mechanics (CSSM) framework and the similarities and differences in behavior between equiaxed semi-solid alloys and soils are discussed.

  相似文献   

16.
利用低过热度浇注技术制备了半固态A356铝合金坯料,研究了半固态温度区间重熔加热时半固态A356铝合金坯料的初生相形貌的转变过程.结果表明,在半固态两相区保温,半固态A356合金的初生相逐渐团球化,该过程随保温温度的升高而加快.半固态A356铝合金晶粒的圆度与保温温度和保温时间的关系不大,但晶粒的尺寸随着保温温度和保温时间的增加而增大.半固态A356合金试样重熔加热最佳工艺制度为583℃下保温30min,其晶粒平均等积圆直径为80μm,晶粒平均圆度为0.83.  相似文献   

17.
The desired starting material for semi-solid processing is the semi-solid slurry in which the solid phase is present as fine and globular particles. A modified solid–liquid mixing (SLM) is reported wherein semi-solid slurry can be produced by mixing a solid alloy block into a liquid alloy, and mechanical vibration is utilized to enhance the mixing. Effects such as liquid alloy temperature, mass ratio, and mixing intensity on the microstructure and the cooling curves during SLM were evaluated. 2D and 3D microstructure analysis of treated A356 aluminum alloy shows that microstructure can be refined significantly with a considerable morphology change in primary Al phase. It is critical that the temperature of mixture after mixing is lower than its liquidus temperature to obtain a valid SLM process. Specially, mixing intensity is identified as a primary factor for a favorable microstructure of semi-solid slurry.  相似文献   

18.
Semi-solid Al2Y/AZ91 magnesium matrix composites slurry was prepared by ultrasonic vibration, effect of ultrasonic vibration temperature and time on microstructure of semi-solid slurry was investigated. The results showed that with the ultrasonic vibration temperature decreasing the solid volume fraction of semi-solid slurry increased. The best ultrasonic vibration temperature was 600 oC. With the increase of ultrasonic vibration time, the average grain diameter of primary а-Mg particles decreased firstly, then increased, the average shape factor increased gradually and decreased slightly after 90 s, and a few rosette dendrites were observed after 120 s. The best semi-solid slurry with average grain diameter of 75 μm and shape factor of 0.7 were gained after the melt was treated by ultrasonic vibration for about 60 s at near liquidus temperature(600 oC). At last, the microstructure evolution mechanism of semi-solid magnesium matrix composites slurry was analyzed by the theories of thermodynamics and kinetics.  相似文献   

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