Microstructure and Dynamic Ultra-Micro Hardness of the As-Cast and Extruded Mg-Al-Ca-Sm Alloys
Microstructure and Dynamic Ultra-Micro Hardness of the As-Cast and Extruded Mg-Al-Ca-Sm Alloys
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DOI：
10.4028/www.scientific.net/amr.26-28.153
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发表时间：
2007-10
期刊：
影响因子：
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通讯作者：
H. Son;Jae Seol Lee;Ji-Min Hong;Dae-Guen Kim;K. Yoshimi;K. Maruyama
中科院分区：
文献类型：
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作者：
H. Son;Jae Seol Lee;Ji-Min Hong;Dae-Guen Kim;K. Yoshimi;K. Maruyama
Mg-5Al-3Ca-2Sm合金的铸态组织由等轴α-Mg基体、（Mg，Al）2Ca共晶相和富Al-Sm金属间化合物组成。由于热挤压变形剧烈，挤压态合金的共晶相向挤压方向伸长，尺寸比铸态合金细化。热挤压后，Mg-5Al-3Ca和Mg-5Al-3Ca-2Sm合金的平均晶粒尺寸分别为4.8 μ m和3.8 μ m。在加卸载硬度试验中，由于Sm细化晶粒和变形量大，加入Sm和挤压后的渗透深度减小。Sm的加入细化了Mg-5Al-3Ca合金的晶粒，并在晶界和α-Mg基体上形成了富Al-Sm的金属间化合物，使合金的硬度高于Mg-5Al-3Ca合金。挤压态Mg-5Al-3Ca-2Sm合金在高温下的硬度最大。
The as-cast microstructure of Mg-5Al-3Ca-2Sm alloy consists of equiaxed α-Mg matrix, (Mg, Al)2Ca eutectic phase and Al-Sm rich intermetallic compounds. This eutectic phase of the extruded alloys was elongated to extrusion direction and size of this phase was finered compare to that of as-cast alloys because of severe deformation during hot extrusion. After hot extrusion, the average grain size of Mg-5Al-3Ca and Mg-5Al-3Ca-2Sm alloys was 4.8 *m and 3.8 *m, respectively. In load-unload hardness test, penetration depth was decreased with added Sm and after extrusion procedure because of grain size refining by addition Sm and large deformation. Hardness value of the alloys containing Sm was higher than that of Mg-5Al-3Ca alloy due to grain refining and formation Al-Sm rich intermetallic compound at gain boundary and α-Mg matrix. Maximum hardness value was obtained at the extruded Mg-5Al-3Ca-2Sm alloy at elevated temperatures.