Al-5Ti-1B合金线对纯铝的晶粒细化作用

采用电磁搅拌连续铸挤Al-5Ti-1B合金线对纯铝进行细化试验,研究了熔体静置时间、合金线添加量以及添加温度对晶粒细化效果的影响。结果表明,熔体静置时间为5min时,合金线的细化效果较好,静置时间在120min之内,细化效果未出现明显衰退现象;随着合金线添加量的增加,细化后纯铝的晶粒尺寸逐渐减小;细化温度为700～730℃时,Al-5Ti-1B合金线具有较好的细化效果,温度为690℃时,晶粒局部粗大,温度为740℃时,细化后纯铝晶粒尺寸较大。     

Grain refining technique of AM60B alloy by Al-Ti-B master alloy

The effects of grain refining parameters on grain size of AM60B magnesium alloy have been investigated using an Al-5Ti-1B master alloy as refiner; and an appropriate refining technique has been developed. The results indicate that the Al-Ti-B master alloy is an effective grain refiner for AM60B alloy and the grain size can be decreased from 348 μm to 76 μm. Raising the addition temperature or the pouring temperature is beneficial for grain refinement; while for the addition amount and holding time, there is an optimal value. The appropriate grain refining technique is that 0.3% Al-Ti-B master alloy is added at 780oC and then the melt is held for 30 min before pouring. The above phenomena can be explained by the refining mechanisms that have been proposed from the related studies on Al and Mg alloys and theoretical analysis.     

精炼处理对Al-Si-Mg合金熔体中TiB2粒子的影响

加入Al-5Ti-1B中间合金的Al-Si-Mg合金熔体,经N2气精炼处理后试样的晶粒尺寸较精炼处理前明显粗化,即精炼处理显著削弱了Al-5Ti-1B中间合金对Al-Si-Mg合金的细化效果。分析认为,精炼过程中一部分TiB2粒子及其聚集团极易被N2气泡捕获并游离出熔体,使异质形核衬底数目大幅减少。针对精炼对细化效果的不利影响,提出了两种解决方案,即采用Al-5Ti-0.6B-0.2C中间合金或先精炼后添加细化剂的操作工艺。     

不同加钛方法对6063合金细化的研究

加钛方式不同，钛含量不同，对铝及其合金的晶粒细化效果不同。对比研究了用电解低钛铝合金、加Al—5Ti中间合金、Al—5Ti—1B中间合金及电解低钛铝合金加Al—B中间合金4种加钛方式及不同钛含量对6063合金的晶粒细化效果。研究结果表明：不同的加钛方式对6063合金均有明显的细化效果，随着钛含量增加，晶粒逐渐变细；钛含量相同时，电解加钛的细化效果优于Al—5Ti中间合金的细化效果；当合金中含有硼时，钛含量相同时，电解加钛加Al—B中间合金的细化效果优于加Al—5Ti—1B的细化效果。     

Grain Refining Efficiency of SHS Al-Ti-B-C Master Alloy for Pure Aluminum and Its Effect on Mechanical Properties

A new Al-5Ti-0.75B-0.2C master alloy was successfully prepared by self-propagating high-temperature(SHS)reaction from an Al-Ti-B_4C system with molten Al.Microstructure and phase characterization of the prepared Al-5Ti-0.75B-0.2C master alloy show that the nearly spherical TiC particles,hexagonal or rectangular TiB_2 particles,and blocklike TiAl_3 particles distribute uniformly in the aluminum matrix.Grain refining test on commercial pure aluminum indicates that Al-5Ti-0.75B-0.2C master alloy exhibits a better grain refining performance than Al-5Ti-lB master alloy.By addition of 0.2 wt%Al-5Ti-0.75B-0.2C master alloy,the average grain size of a-Al can be effectively refined to160 ± 5 μm from about 3000 μm,and the tensile strength and elongation are increased by about 20%and 14.1%due to the grain refinement.     

中间合金对A356.2合金细化的效果

采用铝业协会制订的TP-1型标准测试法,对Al-10RE、Al-5Ti-1B、Al-5Ti-1B-10RE等中间合金对A356.2合金的细化效果进行评价,以优化铝合金轮毂制造过程中合金熔体细化处理工艺。结果表明, Al-5Ti-1B-10RE中间合金中的RE不仅可以有效抑制晶粒尺寸的衰退,而且在一定程度上改善Ti、B、Sr对A356.2合金显微组织的细化和变质效果;TP-1型晶粒度检测法是一种简单、直观、准确的中间合金细化效果在线评价方法。     

细化变质处理对铸造Al-7.5Si-4Cu合金力学性能和组织的影响(英文)

研究了单一和复合Al-5Ti-B、RE和Al-10Sr细化变质剂对砂型铸造Al-7.5Si-4Cu合金力学性能、显微组织、细化变质效果及其金属间化合物变化的影响。结果表明:与单一细化变质处理以及铸态相比,经过添加质量分数为0.8%的Al-5Ti-B、0.1%的RE和0.1%的Al-10Sr细化变质剂复合细化变质处理后铸造Al-7.5Si-4Cu合金的力学性能和显微组织都得到了显著改善。对于单一细化变质处理,加入0.8%的Al-5Ti-B中间合金后,合金的抗拉强度和布氏硬度得到大幅度提高,并且细化了α(Al)相。加入0.1%的RE中间合金后,合金的伸长率得到了最大程度的提高。这是因为RE的加入使铝合金熔液而得到净化,同时改变了金属间化合物的形状。而加入0.1%的Al-10Sr变质剂后,合金的屈服强度得到改善,但其他性能的改善有限。Al-10Sr变质剂对共晶硅具有较强的变质作用,但使得铝合金熔体含气量增加并形成严重的柱状晶组织。利用硅相的平均面积和长宽比描述细化变质效果得到的结论与力学性能和组织分析的结果相同。     

Al-5Ti-1B和Al-P中间合金对Al-Si合金的联合变质作用

研究了Al-5Ti-1B和Al-P中间合金对Al-Si活塞合金组织和性能的影响。结果表明，加入0．2％Al-5Ti-1B中间合金能使经Al-P中间合金变质过的ZL109合金的共晶团和初晶硅进一步细化，抗拉强度也明显提高。随着Al-5Ti-1B加入的增加这种细化作用逐渐减小，当Al-5Ti-1B的加入量为2％时甚至使ZL109中的初晶硅变粗，抗拉强度也随之降低。     

高洁净度Al-5Ti-1B晶粒细化剂的制备与微结构特征

在传统氟盐法工艺的基础上,利用电磁场作用下合金化处理、旋转除气及高效过滤等技术,提出了一种制备高洁净度Al-5Ti-1B晶粒细化剂的新工艺。试验研究表明,采用新的高洁净度制备工艺使Al-5Ti-1B合金中的杂质减少、洁净度大幅度提高。微结构表征显示采用新工艺制备的Al-5Ti-1B合金中TiAl3相和TiB2粒子分布均匀,尺寸细小,分别为5～30μm和0.37～1.24μm,能够很好地满足高品质铝合金细化处理的要求。并对Al-5Ti-1B细化剂的细化机理进行了讨论,为工业生产中进一步提高Al-5Ti-1B细化剂的质量提供理论依据和技术参考。     

Al-5Ti-1B对AZ31合金组织与性能的影响

研究了Al-5Ti-1B中间合金不同添加量对AZ31镁合金显微组织和力学性能的影响。结果表明,在AZ31镁合金中添加Al-5Ti-1B中间合金有利于组织性能的改善。在试验中,添加量控制在0.5%为佳,此时,合金晶粒尺寸达到最小,约为170μm,是AZ31镁合金未添加细化剂时晶粒尺寸的30%,抗拉强度及伸长率分别达到最大。AZ31镁合金组织性能的变化主要与Al-5Ti-1B中间合金中的游离Ti和TiB2有关。     

A novel fading-resistant Al-3Ti-3B grain refiner for Al-Si alloys

Al-Ti-B refiners with excess-Ti perform adequately for wrought aluminum alloys but inefficiently in the case of foundry alloys. The high content of silicon in the latter, which forms silicides with Ti and severely impairs the refining potency of the nuclei, is known to be responsible for the poor performance. Hence, new grain refiners, such as Al-3B and Al-3Ti-3B master alloys with excess-B have been developed with well documented advantages for Al-Si alloys. It is very desirable to involve TiAl₃ particles in the Al-3Ti-3B master alloy to maximize its grain refining efficiency. However, fading phenomenon is a key drawback for application of the TiAl₃-containing refiners in aluminum foundry. In the present work, new Al-3Ti-3B grain refiners, containing TiB₂, AlB₁₂ and TiAl₃ particles were developed with an aim to prolong the acting time after inoculation. The results showed that inoculation of Al-7Si alloy with thus meliorated Al-3Ti-3B grain refiner has produced a fine grain structure which was approximately maintained up to 30 min.     

电磁搅拌连续铸挤Al-5Ti-1B合金的组织与晶粒细化效果

采用电磁搅拌连续铸挤工艺成形Al-5Ti-1B合金线,利用等离子体发射光谱仪、光学显微镜、X射线衍射仪和扫描电镜研究了Al-5Ti-1B合金线的组织与晶粒细化效果,并与Al-5Ti-1B合金锭进行了比较。结果表明,通过中间包电磁搅拌和连续铸挤成形过程中半固态剪切搅拌和剧塑性变形作用,可细化TiAl3相尺寸,改善TiB2粒子的分布状态,TiAl3相为细小块状,TiB2粒子弥散分布于α-Al基体中。Al-5Ti-1B合金线的晶粒细化能力增强,纯铝中添加0.2%的Al-5Ti-1B合金线静止5min,晶粒平均尺寸可细化至223μm,静止180min,晶粒平均尺寸为316μm。     

Al-3Ti-3B中间合金对AZ31镁合金晶粒细化的影响

利用OM、XRD、SEM和EPMA等手段研究了Al-3Ti-3B细化剂对AZ31镁合金微观组织的影响。结果表明,添加适量的Al-3Ti-3B细化剂能使铸态AZ31镁合金粗大的树枝晶转变为均匀的等轴晶;加入量为0.4%时取得了较好的细化效果,固溶处理后的AZ31镁合金平均晶粒尺寸由300μm减小到50μm。TiB2和AlB2粒子的异质形核作用是促使晶粒细化的主要机制,且TiB2粒子在晶界上的偏聚可进一步阻碍晶粒长大。     

Microstructural Evolution and Grain Refining Efficiency of Al-10Ti Master Alloy Improved by Copper Mold Die Casting

The microstructural evolution and grain refining efficiency of sub-rapidly solidified (SRS) Al-10Ti master alloy has been studied. The results show that the mean size of Al₃Ti particles in the SRS Al-10Ti master alloy decreased significantly and the morphology changed from strip-like to blocky and short rod-like compared with the conventional Al-10Ti master alloy. Grain refining experiments show that the SRS Al-10Ti master alloy is more effective than the conventional master alloy for refining Al-7Si alloy. The conversion rate of columnar to fine equiaxed grain structure in the Al-7Si alloy was promoted by the addition of SRS master alloy, and the microhardness of Al-7Si alloy increased. The mechanisms of grain refinement of aluminum by inoculation with improved Al-10Ti master alloy are discussed based on the solute theory. The decrease in size, increase in quantity, and change in morphology of Al₃Ti particles are considered as the reasons for the improvement of microstructure and microhardness.     

Grain refinement of AZ31 magnesium alloy by new Al-Ti-C master alloys

New Al₄C₃-containing Al-Ti-C master alloys (Al-0.6Ti-1C and Al-1Ti-1C) were developed by introducing Ti element into Al-C melt using melt reaction method, in which most of the TiC particles distribute around Al₄C₃ particles. It is believed that most of the C firstly reacts with Al melt and form Al₄C₃ particles by the reaction Al(l)+C(s)→Al₄C₃(s), and after adding Ti into the Al-C melt, the size of Al₄C₃ particles is decreased and the distribution of Al₄C₃ is improved through the reaction Ti(solute)+Al₄C₃(s)→TiC(s)+Al(l). With the addition of 1% Al-1Ti-1C master alloy, the average grain size of AZ31 is reduced sharply from 850 μm to 200 μm, and the grain morphology of α-Mg transits from a fully-developed equiaxed dendritic structure to a petal-like shape. Al-C-O-Mn-Fe compounds are proposed to be potent nucleating substrates for primary Mg. Appropriate addition of Ti is believed to increase the grain refinement efficiency of Al₄C₃-containing Al-Ti-C master alloys in AZ31 alloy.     

微量Mg、Si对Al-Ti-C中间合金晶粒细化效果的促进作用

研究结果表明：微量的Mg和Si均能促进Al-Ti-C中间合金对工业纯铝和6063合金等铝合金的晶粒细化作用;在细化温度相同的条件下,与Si相比,Mg对Al-Ti-C中间合金细化效果具有更大的促进作用,微量的Mg可以抑制Al-Ti-C中间合金晶粒细化的“温度效应”;铝熔体中同时存在微量的Mg和Si时Al-Ti-C中间合金的细化效果更好,初步探讨了这两种微量元素促进Al-Ti-C中间合金细化效果的机理。     

Al-5C中间合金对AZ31镁合金的细化机理

采用粉末原位合成工艺制备Al-5C中间合金,研究Al-5C中间合金对AZ31镁合金晶粒细化的影响及细化机理。结果表明：Al-5C中间合金由α（Al）和 Al 4 C 3两相组成,Al 4 C 3颗粒的尺寸分布由烧结时间控制。Al-5C中间合金能显著地细化AZ31镁合金晶粒尺寸,当Al-5C中间合金添加量低于2%时,随着Al-5C中间合金添加量的增加,AZ31镁合金晶粒尺寸减小。晶粒细化机理是由于 Al4C3与 Mn 反应生成的Al-C-Mn 颗粒能作为初生α-Mg晶粒的异质形核基底,从而细化晶粒。     

Effects of Al-10Sr master alloys on grain refinement of AZ31 magnesium alloy

The effects of Al-10Sr master alloys on grain refinement of AZ31 magnesium alloy were investigated, and the refinement efficiency of different Al-10Sr master alloys （commercial, solubilized, rolled and remelted＋rapidly cooled） was compared and analyzed. The results indicate that the morphology and size of Al4Sr phases in the microstructures of different Al-10Sr master alloys, are of great difference. For the commercial Al-10Sr master alloy, the Al4Sr phases evolve from coarse block shape to relatively fine block shape after being dissolved at 500 ℃ for 4 h and followed by water quenching; but after being rolled at 300 ℃ for 50% reduction or remelted and followed by rapid cooling, the Al4Sr phases mainly exhibit fine granule and fibre shapes. In addition, the different Al-10Sr master alloys can effectively reduce the grain size of AZ31 magnesium alloy, but their refinement efficiency is different. The refinement efficiency of the Al-10Sr master alloy obtained by remelting and rapid cooling is the best, then the rolled, solubilized and commercial Al-10Sr master alloys are in turn. The difference of refinement efficiency for different Al-10Sr master alloys may be related to the dissolution rates of Al4Sr phases with different morphologies and sizes in the melt of AZ31 magnesium alloy.     

Al-Ti、Al-Ti-C中间合金对AZ91D镁合金组织和性能的影响

研究了Al-5Ti、Al-5Ti-0．25C和Al-8Ti-2C中间合金对AZ91D镁合金的组织、力学性能和耐腐蚀性能的影响。结果表明,添加Al-5Ti中间合金使晶粒粗化,而添加Al-5Ti-0．25C和Al-8Ti-2C中间合金使晶粒细化,Al-8Ti-2C中间舍金的细化效果明显且细化后组织细小均匀;添加Al-5Ti中间合金使合金的力学性能降低,而添加Al-5Ti-0．25C和Al-8Ti-2C中间合金均使合金的拉伸强度和伸长率得到了提高;添加Al-5Ti、Al-5Ti-0．25C和Al-8Ti-2C中间合金均使合金的耐腐蚀性能得到了改善。对于AZ91D合金而言,Al-8Ti-2C中间合金是一种良好的晶粒细化剂。     

Response of an Al—Cr alloy towards grain refinement by Al—5Ti-1B master alloy

Grain refining of an Al–2%Cr alloy by Al–5Ti-1B master alloy (5/1 TiBAl) has been studied as a function of the addition rate of the grain refiner in the range 0.2–1.2% and holding times up to 120 minutes. This study revealed that an effective grain refinement of Al–2%Cr requires a minimum addition of 1.2% grain refiner as against the 0.2% which is normally required for most of the conventional Al alloys. The work further revealed that the effect of grain refiner starts fading after holding the melt for about 5 minutes, irrespective of the addition rate of grain refiner. The formation of complex aluminides in the presence of Cr seems to be the primary reason for the poor grain refining response of this alloy at low addition rates of grain refiner. At high addition rates, the better grain refining behaviour of the present alloy was found to be essentially due to the availability of finer unreacted nucleating sites (TiAl₃ and TiB₂).