Pengfa FENG
材料科学技术（英）
The influences of preparation conditions of Al-5Ti-B (as-cast and hot-rolled) and Al-10Sr (as-cast and hot-extruded) and melt treatment procedures on the grain refinement and modification performance of A356 alloy are experimentally studied. For the two master alloys, the 50% reduction is sufficient to meet the demands of the efficient grain refinement and modification of A356 alloy. When Al-5Ti-B is introduced into the melt prior to degassing, the grain refinement efficiency of Al-5Ti-B will be greatly increased due to the better dispersity of TiB2 particles. Al-5Ti-B master alloy is less prone to affect the modification effect of Al-10Sr when they are used together.
关键词:
Grain refinement
,
中间合金
,
热变形
,
晶粒细化
,
A356合金
Zheng LIU
金属学报(英文版)
doi:10.1016/S1006-7191(08)60118-0
Semi-solid slurry of A356 alloy was prepared by low superheat pouring and slightly electromagnetic stirring, and the fractal characteristics of morphology in semi-solid primary phase was researched. The fractal dimensions of primary phase morphology in the semi-solid A356 alloy were calculated by the program written to calculate the fractal dimensions of box-counting in the image of solid phase morphology in semi-solid metal slurry. The results indicated that the morphology of primary phase in semi-solid A356 prepared by low superheat pouring and slightly electromagnetic stirring is characterized by fractal dimension, and the primary phase morphology obtained by the different processing parameters has different fractal dimensions. The morphology of primary phase at the different position of ingot has different fractal dimensions, which reflected the effect of solidified conditions at different positions in the same ingot on the morphology of semi-solid primary phase. Solidification of semi-solid alloy is a course of change in fractal dimension.
关键词:
Semi-solid
,
初生相形貌
,
分形
,
A356铝合金 semi-solid, morphology of primary phase, fractal, A356 alloy
Z. Liu
,
W.M. Mao
金属学报(英文版)
The semi-solid slurry of A356 alloy, which is grain-refined by Al-Ti-B master alloy, is prepared by low superheat pouring and slightly electromagnetic stirring. The effects of grain-refine on the morphology and the grain size of the primary α phase in the slurry manufactured are researched. The results indicate that the slurry with particle-like and rosette-like primary α phases can be prepared by low superheat pouring and slightly electromagnetic stirring from liquid A356 alloy grain-refined, in which the pouring temperature can be suitably raised. Compared with the A356 samples without grain-refined, the grain size and particle morphology of primary α phase as well as the distribution of the grain with particle-like or rosette-like along radial in the ingot in A356 are markedly improved by grain-refined.
关键词:
semi-solid
,
null
,
null
,
null
,
null
,
null
徐永东
,
邵志文
,
任静
,
陈大辉
,
郭红燕
兵器材料科学与工程
研究了功率超声作用下的纳米TiN颗粒熔体处理对A356合金微观组织的影响。结果表明：由于纳米TiN与A356合金熔体不润湿，单独加入纳米TiN，合金枝晶减少、初始晶粒细化，而共晶Si相的形貌变化不明显；向熔体中加入纳米TiN后进行功率超声处理，不但合金的初始晶粒细化、枝晶减少，而且共晶Si由长针状转变为短棒状。
关键词:
功率超声
,
纳米TiN
,
A356合金
,
微观组织
刘政
,
谌庆春
,
郭颂
稀有金属
doi:10.3969/j.issn.0258-7076.2013.05.005
研究了稀土Y在亚共晶铝硅合金中诱发稀土-铝共晶反应对铝合金初生α相的细化效应；应用Bramfitt提出的方法,计算了Al-Y共晶反应产物Al3Y与α-Al界面的二维点阵错配度,结果显示两者的二维错配度＜6％,即Al3Y可作为α-Al的异质形核质点,且能达到中等有效形核而起到细化晶粒的作用,并通过实验验证计算结果如下:选用稀土元素Y作为A356合金细化剂的同时,将A356-Y熔体分别在稀土钇-铝共晶温度上、下10℃左右保温t2 min后快速冷却,获得试样的金相组织照片后利用图像分析工具得到A356-Y合金初生α相的平均晶粒尺寸和平均形状因子.实验结果表明:A356-Y合金在Al-Y共晶温度之下保温,可获得较理想的初生α相形貌和较小的晶粒尺寸;结合二维错配的计算结果,可推断初生α相细化的主要原因为异质形核质点的增加:Al-Y共晶反应产物Al3Y与α-Al的二维点阵错配度在中等有效形核范围内,具有细化合金初生α相的作用;另一共晶产物α-Al与初生α相具有相同的晶体结构和点阵常数,则其也可作为异质形核质点而起到细化合金的作用.稀土Y可作为半固态A356合金中初生α相的优质细化剂.
关键词:
A356铝合金
,
稀土钇
,
共晶反应
,
二维错配度
,
半固态
刘洪军
,
王扬虎
,
李亚敏
机械工程材料
采用倾斜板法制备了半固态A356合金浆料,考察了浇注温度、金属液流动距离和冷却板倾斜角度等对其凝固后显微组织的影响.结果表明:倾斜板法通过激冷形核和流动冲击作用,使A356合金中的初生相由枝晶状变为球团状、块状或者蔷薇状的半固态形貌;低的浇注温度、长的金属液流动距离和小的冷却板倾斜角度均有利于形成细小、圆整的初生相,但是也会造成凝固壳的形成或者不均匀组织的倾向增大;适宜的浇注温度为630～640℃、金属液流动距离为800mm、倾斜角度为60°.
关键词:
半固态合金
,
显微组织
,
A356合金
,
倾斜板法
范学义
,
董允
,
林晓娉
,
王铁宝
,
李丹
,
万志永
,
李娅珍
材料热处理学报
通过重熔试验研究Al-5Ti-1B和Al-10Sr中间合金在A356熔体中的遗传效应.结果表明:A356合金经熔体处理后流动性较母材提高17.36%,T6处理后α-Al枝晶细化,二次枝晶间距仅为16.8 pLm,共晶硅圆整,抗拉强度达269 MPa、屈服强度203MPa、伸长率12.5%、硬度92 HBW.伴随重熔,细化变质效果逐渐衰退,熔体质量下降,以致力学性能和流动性下降.试验发现固溶后快淬可减小变质衰退带来的影响.
关键词:
遗传效应
,
变质
,
细化
,
A356铝合金
袁文文
,
陈祥
,
刘源
,
李言祥
稀有金属材料与工程
采用熔体发泡工艺,实现了A356合金500 mm×1000 mm×X不同厚度泡沫铝板材的批量制备.对该工艺方法的増粘、发泡剂加入,泡沫均匀性控制等关键技术进行了系统研究.获得了工厂条件下A356合金泡沫铝块体和板材的优化制备工艺参数.对欠、过发泡,中心大孔,裂纹等缺陷的产生原因进行分析,提出了解决方法.
关键词:
泡沫铝
,
A356合金
,
TiH2
,
板材
张松利
,
赵玉涛
,
陈刚
,
汪长勤
机械工程材料
采用高能超声装置对A356合金熔体进行处理,利用扫描电镜、万能材料试验机等研究了高能超声功率及处理时间对A356合金铸态显微组织和力学性能的影响,并分析了其作用机理.结果表明:对A356合金熔体进行超声处理后合金铸态组织中的硅相逐渐由树枝状变成颗粒状,α-Al相细小圆整;当超声功率为1.2 kW、处理时间为600 s时,处理效果最好;处理时间一定后,随着超声功率的提高,A356合金的抗拉强度、屈服强度和伸长率都增加,最大值可分别达到294.37,207.98 MPa和6.85%,分别为未施加高能超声处理的1.56,1.93和1.10倍;随着高能超声处理时间的延长,A356合金的抗拉强度、屈服强度以及伸长率呈现先升后降的趋势.
关键词:
高能超声
,
A356合金
,
显微组织
,
力学性能
