共查询到20条相似文献,搜索用时 125 毫秒
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Sr-PM复合变质过共晶铝硅合金 总被引:9,自引:1,他引:9
研究了PM和Al-10Sr复合变质过共晶铝硅合金A390.考察了复合变质剂的加入顺序、加入量以及变质的长效性.试验发现:PM和Sr复合变质剂的加入顺序对过共晶铝硅合金A390变质效果影响很大,先加入PM变质剂,后加入Sr变质剂,变质后初晶硅呈现开花状形貌,共晶硅为细小的圆点状;先加入Sr变质剂,后加入PM变质剂,初晶硅变质效果明显优于单独PM变质效果.加入PM质量分数为1%时,Al-10Sr变质剂的最佳加入量为合金质量的0.4%,变质后初晶硅平均尺寸可达到35 μm,而且PM与Sr复合变质具有很好的长效性. 相似文献
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《中国有色金属学报》2019,(1)
为提高高硅Mg-Si-Zn合金的性能,实验通过调整Ca、Y变质剂的含量,研究在Ca变质、Ca-Y复合变质作用下高硅Mg-Si-Zn合金的凝固组织与性能。结果表明:在Mg-4Si-4Zn合金中加入Ca,可使合金凝固组织中初生Mg2Si相由粗大的枝晶形貌转变为细小的矩形块状形貌,共晶组织由粗大的汉字状转变为点棒状;当Ca加入量为0.7%时(质量分数)变质效果最为明显;当Ca加入量超过0.7%后,合金中会形成CaMgSi棒状相,这是Ca变质效果下降的一个主要原因。当合金中Ca加入量为0.7%时,再加入Y会将初生Mg_2Si相由规则平整形貌转变为带有沟壑孔洞的复杂形貌,而相的尺寸基本不发生改变,这使得经Ca-Y复合变质的Mg-4Si-4Zn合金的硬度显著高于Ca单一变质合金的,硬度提高超过10%。 相似文献
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共晶铝硅合金Sr,RE以及P变质处理的研究 总被引:7,自引:1,他引:6
对共晶铝硅合金进行了Sr、RE以及P变质处理的研究。结果表明,锶变质处理后达到最佳变质效果有一定的时间,本实验为90min,其后又有变质衰退现象;稀土是一种良好的变质剂,但Sr、RE复合变质同其单一变质相比,效果差别不明显;P变质对共晶组织也有明显的影响,它可使共晶点左移,从而在共晶成分时也可析出初晶硅,使共晶硅的数量减少,同时共晶硅较为粗大。 相似文献
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采用Al-3P和0.2 mass%Al-5Ti对共晶铝硅合金进行复合变质处理,并对复合变质前后共晶铝硅合金的显微组织和力学性能进行了分析和测试.结果 表明,Al-3P加入量和变质处理温度对共晶铝硅合金的显微组织和力学性能有明显影响.在700℃下采用0.6 mass% Al-3P和0.2 mass%Al-5Ti对共晶铝硅合金进行复合变质处理时,α-Al相体积分数可达到55%,初生α-Al相呈细小枝晶状,硅相呈细小颗粒状.与0.2 mass%Al-5Ti变质处理合金相比,复合变质处理后共晶铝硅合金的抗拉强度和伸长率分别提高28.3%和56.7%,综合力学性能得到明显提高,且其拉伸断口呈现明显的韧性断裂. 相似文献
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Hypereutectic Al-17.5Si (wt pct) and Al-25Si (wt pct) alloys with various content of rare earth Er were prepared by conventional casting technique. The effect of Er on the microstructure and properties of the hypereutectic Al-Si alloys was investigated using optical microscopy, scanning electron microscopy as well as friction and wear tests. It was found that optimal amount of Er exists in modifying the hypereutectic Al-Si alloys. An appropriate addition of Er improved the anti-wear properties, and reduced the friction coefficient of the hypereutectic Al-Si alloys studied. The primary silicon crystals in the hypereutectic Al-Si alloys were refined with the suitable addition of Er element. The modification mechanism was also discussed in this paper. 相似文献
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D. Q. Shi D. Y. Li G. L. Gao 《JOM Journal of the Minerals, Metals and Materials Society》2008,60(11):25-28
Both the theoretical analysis and experiments on Al-Si alloys have shown that a relationship between the surface tension and
the modification of Al-Si alloys exists. A new method for the rapid prediction of the the modification level of Al-Si alloys
by surface tension has been introduced. The quantity of the modifier is found to have the greatest effect, followed by the
time of the modif cation and then the temperature. In Al-Si alloys, when the surface tension is above 530 mN/m, the modification
level is partial. When the surface tension is between 400 mN/m and 530 mN/m, the modification level is moderate. When the
surface tension is below 400 mN/m, the modification level is perfect. 相似文献
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Al-8Ti-2C对Al-P中间合金变质效果的促进作用 总被引:3,自引:1,他引:3
研究了自制Al-P中间合金对共晶及过共晶Al-Si的变质作用,发现该Al-P中间合金对共晶及过共晶Al-Si合金都具有优良的变质效果。同时还发现,当铝合金熔体中加入Al-8Ti-2C中间合金时,Al-P中间合金对两类Al-Si合金的变质效果会增强。当Al-24Si合金中TiC含量为0.03%(以Al-8Ti-2C中间合金方式)时,初晶Si的平均尺寸由原来的47μm细化为41μm,最大尺寸由原来的75μm降为55μm;加入Al-P中间合金和TiC颗粒50min后,就可以出现变质效果,时间再延长,变质效果也不会有更大的提高。当Al-12Si合金中TiC含量为0.03%时,初晶Si的平均尺寸由原来的50μm变为30μm。 相似文献
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Cobalt is generally considered as the element that can promote the high-temperature mechanical properties of Al-Si alloys. In order to develop new hypereutectic Al-Si alloys that can be used at high temperature, the changes of microstructure of Al-20Si-2Cu-1Ni-0.6RE-xCo alloy with different contents of Co were studied in this paper. The results show that, under P-RE complex modification of the alloy melt, the content of Co varying from 0 to 1.5% had little influence on the refining effect of primary Si and modification effect of eutectic Si, but the amount of acicular RE-bearing Al-RE-Ni-Co-Si compounds gradually increased with the increase of Co content. In addition, Co could also modify the morphology of Fe-bearing phases, which solidified as particles instead of long needles. The addition of Co even has an adverse effect on the tensile strength of this RE-containing hypereutectic Al-Si alloy. 相似文献
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利用金相显微镜、DIL402C高温膨胀仪等对Al-Si合金的线膨胀进行了研究。结果表明:对于Al-Si合金,硅含量越高,其线膨胀系数越小,随温度变化幅度减小;随着温度升高,磷变质比锶变质的线膨胀系数变化幅度小,合金更加稳定;此外,T6热处理也显著降低Al-Si合金的线膨胀系数。通过对合金线膨胀系数和微观组织的对比观察发现:硅相的形态和体积分数对Al-Si合金的线膨胀系数产生重要影响。初晶硅体积分数的增加和初晶硅的析出能够显著降低Al-Si合金的线膨胀系数,共晶硅的形态对合金线膨胀系数也有一定的影响,共晶硅为短棒状、颗粒状时(尤其经热处理后),合金的线膨胀系数也显著降低。 相似文献
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铝合金在有色合金中应用最为广泛,而A1-Si类合金约占铝合金的80%,其应用范围日益扩大.虽然Al-Si类合金大多为多元合金,但该类合金的组织中A1-Si共晶体通常占总体积的50%~90%.因此,掌握变质处理对Al-Si共晶凝固的作用及规律,是控制该类合金铸件组织与性能的技术关键之基础.本文以变质元素对A1-Si共晶结晶的作用效果、规律及相关机制为主线,着重对近年该方面的主要研究进展和重要结论进行了综述. 相似文献
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Zu Fangqiu Li Xiaoyun 《中国铸造》2014,(4):287-295
Being used more and more widely in engineering,AlSi alloys comprise about 80%of all kinds of aluminum alloys,which are the most widely utilized nonferrous alloys.Although most Al-Si alloys consist of multiple components,the eutectics in the structure accounts for 50%-90%of the sum volume of such alloys.Therefore,understanding the modification mechanism and function rules of the AlSi eutectic solidification is the technical key in controlling the structures and properties of such casting alloys.The present paper chiefly reviews recent investigation developments and important conclusions along the lines of the functions of modification elements and their modification mechanism in the eutectic solidification of Al-Si alloys. 相似文献