Fabrication of Premium Magnesium Castings by Semi-solid Forming Process

采用半固态成型工艺制造优质镁铸件

• 批准号: 11225207
• 负责人: KAMADO Shigeharu
• 金额: $ 41.98万
• 依托单位: Nagaoka University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11225207/
• 关键词: Mg-Zn-Al Alloy; Semi-solid Forming Process; filling into Thin Cavity; Tensile Properties; Focused Ultrasound; In-Line Monitoring; Porous Material; Pulse Electric Current Sintering; 薄肉充填性; 固相粒子の球状化; 時効特性; 成形性; ミクロ組織

Our research group aims to establish elementary fabrication processes for high qualification of magnesium alloys using semi-solid forming process, including that for high performance raw materials. The results are summarizes as follows(1)In "Search for magnesium alloys having good fluidity and adequate tensile properties", the results show that high Zn and Al contents lead to an increase in the amount of compounds that crystallize at low temperatures and the heat generated from the eutectic reactions becomes so large that the semi-solid forming is possible at 465℃ and 535℃ in the alloys containing Al+Zn contents of 20mass% and 15mass%, respectively. These temperatures are more than 100℃ lower than die-casting temperature for conventional magnesium alloys. The addition of small amount of Ca or Sr remarkably refines the eutectic compounds, which are useful for fluidity at semi-temperatures, resulting in suitable elongation and comparable strength with conventional die-casting alloys.(2)M … More agnesium based porous materials are made by Pulse-Electric-Current-Sintering (PECS) method using cut chips. Commercial ingots of AZ91D and AM60B alloys and extruded AZ31 alloy were selected as raw materials in order to change th amount of eutectic compounds and the range of semi-solid temperatures. In well-joined parts of porous samples of AZ91D and AM60B alloy, Mg-Al compounds crystallize, while the aluminum content at the joined part of AZ31 porous sample is concentrated. This means that the non-equilibrium solidified Mg-Al compound is preferentially remelted by rapid heating during PECS. Thus the difference in the microstructures of the joined parts is caused by the different aluminum contents of the alloys. The condition for making the well-joined porous materials using PECS processi s to use alloys that have large amount of low melting compounds and large semi-solid temperature range, resulting in large absorbing energy in compressive test. The plateau stresses of the porous materials investigated in this study largely depend on pore ration in the range from 1.3 to 37.3MPa.(3)In "in-line monitoring of magnesium alloy melt by using focused ultrasound to aim at an in-situ detection of inclusions during liquid recycling process, it is found that an usage of metal-sprayed buffer rod and Focused Ultrasound with a frequency of 5MHZ enable to clearly detect reflected pulse echo from iron block even in a molten magnesium alloy.(4)In "production of magnesium alloys for semi-solid casting on the basis of spheroidizing mechanism of primary crystals", a newly developed processing route is applied in order to refine and to spheroidize primary crystals by insertinga rod, which acts as a nucleation site for primary crystals, into the molten metal and rotating it before solidified specimen. The primary crystals tend to float on the top surface of the molten metal because solid density is lower than the liquid. THerefore, the molten metal is stirred using an inverted T-shaped rod near the bottom of the melt and followed by decreasing the solidification time at the temperature interval from recalescance to quenching. As a result, this process successfully produces an ingot having homogenous fine and spherical primary crystals with an average grain size of 73μm Less

本课题组的主要目标是建立半固态成形镁合金的基本制造工艺，包括高性能原材料的制造工艺。结果总结如下：（1）在“寻找具有良好流动性和足够拉伸性能的镁合金”中，结果表明，高Zn、Al含量使合金中低温晶化的化合物数量增加，共晶反应产生的热量增大，使含Al+的合金在465℃和535℃下均能实现半固态成形Zn含量分别为20质量%和15质量%。这些温度比常规镁合金的压铸温度低100℃以上。少量Ca或Sr的加入显著细化了低共熔化合物，这对于在半温下的流动性是有用的，导致与常规压铸合金相当的强度和适当的延伸率。（2）M ...更多信息 采用脉冲电流烧结法（佩奇）制备了镁基多孔材料。以AZ 91 D、AM 60 B工业铸锭和挤压AZ 31镁合金为原料，通过改变共晶化合物的含量和半固态温度范围，研究了不同共晶化合物含量对AZ 31镁合金半固态温度的影响。在AZ 91 D和AM 60 B多孔试样的结合处，Mg-Al化合物结晶，而AZ 31多孔试样的结合处铝含量集中。这意味着非平衡凝固的Mg-Al化合物在佩奇期间优先通过快速加热而重熔。因此，连接部件的显微组织的差异是由合金的不同铝含量引起的。采用佩奇工艺制备连接良好的多孔材料的条件是使用具有大量低熔点化合物和大的半固态温度范围的合金，从而在压缩测试中产生大的吸收能量。多孔材料的平台应力在1.3 ~ 37.3MPa范围内主要取决于孔隙率。(3)In“利用聚焦超声对镁合金熔体进行在线监测，目的是在液体回收过程中原位检测夹杂物，发现使用金属喷涂缓冲棒和频率为5 MHz的聚焦超声能够清楚地检测来自铁块的反射脉冲回波，即使在熔融镁合金中。(4)In在“基于初生晶体球化机理的半固态铸造镁合金的生产”中，采用了一种新的工艺路线，即在凝固试样之前，将作为初生晶体形核位置的棒插入熔融金属中并旋转棒，以细化初生晶体并使初生晶体球化。由于固体密度低于液体密度，初生晶体倾向于浮在熔融金属的顶面上。因此，使用靠近熔体底部的倒T形杆搅拌熔融金属，然后在从淬火到淬火的温度间隔下减少凝固时间。结果，该工艺成功地生产出具有均匀细小球形初晶的铸锭，平均晶粒尺寸为73μm Less

项目成果

Y.Yoshida: "Low Temperature Superplasticity of ECAE Processed Mg-10%Li-1 %Zn Alloy"Materials Transactions. 43. 2419-2423 (2002)

Y.Yoshida:%20“低%20温度%20超塑性%20of%20ECAE%20加工%20Mg-10%Li-1%20%Zn%20合金”材料%20Transactions.%2043.%202419-2423%20(2002)

M.Zheng: "Aging Behavior of Squeeze Cast SiCW/AZ91 Magnesium Matrix Composite"A348. 67-75 (2003)

郑先生：“挤压铸造SiCW/AZ91镁基复合材料的时效行为”A348。

Y.Yoshida: "Texture Development of AZ31 Magnesium Alloy during ECAE Processing"Material Science Forum. 419-422. 533-538 (2003)

Y.Yoshida：“ECAE加工过程中AZ31镁合金的织构发展”材料科学论坛。

井上誠: "AM60Bマグネシウム合金の真空蒸留精製"軽金属. 51. 285-289 (2001)

井上诚：“AM60B镁合金的真空蒸馏提纯”轻金属51。285-289（2001）。

平賀仁: "マグネシウム合金薄板のレーザ溶接におけるレーザ波長とシールドガスの影響"溶接学会論文集. 19. 591-599 (2001)

Hitoshi Hiraga：“激光波长和保护气体对镁合金薄板激光焊接的影响”日本焊接学会会议记录 19. 591-599 (2001)。