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Al-Si dendrite structure. The microstructure of the stir zone (SZ) is very different from that of the BM. The eutectic Si and SiC particles are dispersed homogeneously in primary Al solid solution. The thermo-mechanically affected zone (TMAZ), where the original microstructure is greatly deformed, is characterized by dispersed eutectic Si and SiC particles aligned along the rotational direction......
; 北京联合大学应用技术学院!北京100101 摘 要: 研究了喷射沉积高硅铝合金在半固态触变成形过程中的规律.结果表明 :喷射沉积Al 2 0 %Si, Al 30 %Si, Al 30 %Si 2 %Ni, Al 30 %Si 2 %RE和Al 30 %Si 2 %Ni 2 %RE具有良好的半固态触变成形性能.... The microstructures become more homogeneous and the densities increase notably after semisolid thixoforming. Keyword: spray form; hyper eutectic Al Si alloy; semi solid......
度等力学性能的提高,这一问题还未见系统研究.不仅如此,活塞,汽缸等零部件不但要考虑强度,硬度,耐磨性特别是高温耐磨性也是重要的力学性能指标.目前高硅Al-Si合金的耐磨性研究较少,高温条件下的研究更少[8],并且Al-Si合金的摩擦磨损行为与Si相形貌,尺寸,分布间的关系一直存在意见分歧[9],如LIU等[10]和孙淑红等[11]均发现Sr或P变质处理后合金的耐磨性明显改善,但CLEGG等[12...化Al-25Si合金获得不同组织形态,研究不同Si相形貌和组织形态条件下的力学行为变化. 1 实验 1.1 试验原料 试验所用的原料为纯度为99.7%(质量分数,下同)的工业纯铝锭,纯度为99.9%的高纯硅,变质剂采用山东吕美熔体技术有限公司生产的Al-3P和Al-10Sr中间合金. 1.2 试验工艺流程 将铝锭在中频感应炉中熔化,升温至750 ℃左右时按所需比......
. Microstructure observations indicated that residual eutectic phases distributed at the grain boundaries were discontinuous and appeared to be small particles in lower Si content alloys; the residual eutectic phases distributed at the grain boundaries were partially continuous and appeared to be films in higher Si content alloys. These phenomena could explain why Si content adversely affected......
of the primary α(Al) phases, Chinese script Al6(FeMn) phases, and eutectic Al2Cu phases, respectively. Similarly, the DSC curve of the alloy with 1.1% Si exhibits three distinct endothermic peaks at 649.6, 535.2 and 525.5 °C, corresponding to the melting of the primary α(Al) phases, eutectic Al2Cu phases, and eutectic Si phases, respectively. With increasing Si content, the endothermic peaks of Al6......
呈上升趋势；Al-7Si-0.3Mg合金的抗拉强度和屈服强度上升,伸长率却明显下降；拉伸过程中Al-1Si-0.3Mg合金中位错在晶界塞积,易使相邻晶粒内位错源启动,使合金具有较高的塑性；Al-7Si-0.3Mg合金的位错在Si相边界塞积,使相邻晶粒内位错源难以启动,从而造成合金具有较高的强度. 关键词:铝硅合金；低温；拉伸性能；位错；硅相 中图分类号:TG146.3 ...行拉伸测试发现,Si相破裂数量随着温度的降低而增加.OSAMU等[25-26]通过反复变形热处理方法细化过共晶铝硅合金中的初生Si相,使低温伸长率显著提高.关于铸造Al-Si合金低温性能发生变化的原因却鲜有研究报道.本文作者通过对铸造Al-1.0Si-0.3Mg和Al-7Si-0.3Mg合金在低温条件下拉伸性能的分析,讨论Si相对铸造Al-Si合金低温下强度和塑性的影响规律及原因. 1 ......
, and later the refined silicon is recovered by super gravity. Al-Si alloy is a typically binary eutectic system. Alloying MG-Si with Al is a process of redistribution of impurities in silicon by taking...-Si alloy is composed of uniformly distributed needle-like Si crystals and surrounding Al-Si eutectic, which results in the difficult separation of primary silicon and ineffective acid leaching......
were significantly refined from coarse block-like and irregular polygonal shapes into fine flaky shapes, while eutectic Si particles were modified from coarse and needle-like into fine and rod- or coral... explored by the means of SEM and EPMA. Key words: Al-18Si-4Cu-0.5Mg alloy; primary Si; eutectic Si; La-Ce addition; mechanical properties 1 Introduction Hypereutectic Al-Si alloys are important......
Solidification structure of eutectic Al-Si alloy under a high magnetic field-aid-electromagnetic vibration Yunbo ZHONG1,Kang DENG1,Weili REN1,Zhongming REN1,Jianbo YU1 (1.Department of Materials... may be attributed to the convection caused by electromagnetic vibration. Strong convection may break co-operative growth of eutectic phases to form polyhedral Si grains and non-dendritic α-A1. Key......
重要结构材料[1].目前工业中应用较多的ZL101和ZL102合金均为亚共晶铝硅合金,其铸态组织为共晶体(α(Al)+Si)和初生α(Al)基体相.Si是Al-Si系合金中的第二相,在没有经过变质处理或细化时,一般在共晶体中呈粗大的片状,甚至是粗大的多角板状,对合金的基体起到了严重割裂效果,致使合金的力学性能特别是塑韧性下降[2-3].因此,采用先进工艺细化铝硅合金中的硅相和基体组织,控制硅相的分布,形状和大小,以提高合金综合力学性能是材料研究者近年来研究的重点. 目前,铝硅合金改变共晶硅形貌的主要方法有振动变质法,温度处理法以及化学变质剂法等,工业上主要采用加入变质剂的方法来实现对硅相的细化[4-6].其中Na,Sr的变质效果最好.金属钠(Na) [7]对Al-Si共晶合金的共晶组织有很好的变质作用,但存在Na极易烧损,变质有效时间短,吸收率低,并且含量难预测等问题.借助先进的大塑性变形......
