文章摘要
超重力场和稀土La变质对Al-14.5Si合金组织及硬度的影响
Effect of super-gravity field and rare earth La modification on microstructure and hardness of Al-14.5Si alloy
投稿时间:2019-06-12  
DOI:
中文关键词: Al-Si合金  超重力场  稀土La  共晶硅  晶粒细化  细化变质  硬度
英文关键词: Al-Si alloy  super-gravity field  rare earth La  eutectic silicon  grain refinement  refinement and modification  hardness
基金项目:国家自然科学基金资助项目(51904213);中国博士后科学基金资助项目(2018M642930).
作者单位E-mail
苏胤 武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北 武汉,430081 1124468167@qq.com 
甘章华 武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北 武汉,430081  
鲁越辉 武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北 武汉,430081  
王耀 武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北 武汉,430081  
胡志奎 武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北 武汉,430081  
吴传栋 武汉科技大学省部共建耐火材料与冶金国家重点实验室,湖北 武汉,430081  
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中文摘要:
      利用超重力场凝固技术和稀土La变质方法制备Al-14.5Si合金铸锭,研究了3000g超重力场下La含量对Al-14.5Si合金组织及硬度的影响。结果表明,3000g超重力场下凝固的Al-14.5Si合金铸锭主要分为边部和芯部两个区域。芯部占主要部分(14~16 mm),在水平和垂直方向的组织都较为均匀,为超细共晶硅组织; 边部厚度约为2~3 mm,组织共晶硅较为粗大。水平方向上,铸锭显微硬度波动较大,中心区域最高;垂直方向上铸锭显微硬度波动较小。随着La含量的增加,共晶硅尺寸呈现先降低后增加的趋势,当La含量为0.6%时,晶粒细化程度最高,芯部共晶硅尺寸最小,平均直径约为0.25 μm,平均长度约为0.37 μm;芯部显微硬度随La含量增加呈先增加后降低的趋势,当La含量为0.4%时,铸锭芯部平均硬度最高可达HV91,相较普通重力场下未变质合金提升了48.2%。由此可见,超重力和稀土La变质对Al-14.5Si合金芯部共晶组织的细化及硬度的提升起到正协同作用。
英文摘要:
      Al-14.5Si alloy ingots were prepared by the method of super-gravity field solidification and rare earth La modification. The effects of La content on the microstructure and micro-hardness of Al-14.5Si alloy under 3000g super-gravity field were studied. The results show that the Al-14.5Si alloy ingots solidified under the 3000g super-gravity field are mainly divided into two regions:the edge and the core. The core is the main part with thickness of 14~16 mm, and the microstructure in horizontal and vertical directions is relatively uniform, which mainly consists of ultra-fine eutectic silicon structure. The thickness of the edge region is about 2~3 mm, and the eutectic silicon structure is coarser. Along the horizontal direction, the microhardness of the ingot fluctuates greatly and the value reaches the highest in the central area, while the microhardness fluctuates very little along the vertical direction. With the increase of La content, the eutectic silicon size first decreases and then increases. When the La content is 0.6%, the grain refinement degree is the highest, and the core eutectic silicon size is the smallest with the average diameter and length at about 0.25 μm and 0.37 μm, respectively. The microhardness of core region of the ingot increases first and then decreases with the increase of La content. When the content of La is 0.4%, the average hardness of the ingot core reaches the highest HV91, which is 48.2% higher than that of the normal gravity field. It can be seen that super-gravity and rare earth La modification play a positive synergistic effect on the refinement of the eutectic structure in core area and the hardness improvement of the Al-14.5Si alloy.
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