Effect of Mg17Al12 precipitates on the microstructural changes and mechanical properties of hot compressed AZ91 magnesium alloy
Effect of Mg17Al12 precipitates on the microstructural changes and mechanical properties of hot compressed AZ91 magnesium alloy
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DOI：
10.1016/j.msea.2009.05.032
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发表时间：
2009-10
期刊：
影响因子：
6.4
通讯作者：
S. W. Xu;N. Matsumoto;S. Kamado;T. Honma;Y. Kojima
中科院分区：
文献类型：
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作者：
S. W. Xu;N. Matsumoto;S. Kamado;T. Honma;Y. Kojima
在热压缩过程中，Mg 17 Al 12（β）析出相对415°C-24 h均匀化AZ 91合金的组织变化有显著影响。当在300°C和350°C下压缩时，动态再结晶（DRX）仅在晶界附近发生，在新DRX的晶界处具有不连续的β沉淀物钉扎。随着压缩温度的升高和应变速率的降低，β相析出区扩大，但钉扎相数量减少，导致动态再结晶率和平均晶粒尺寸增大。在压缩比仅为50%的情况下，在350°C和0.2s-1的应变速率下压缩的试样（指定为350°C-0.2s-1压缩试样）显示出334 MPa的极限拉伸强度（UTS）、195 MPa的0.2%屈服强度（PS）和17.9%的足够延伸率。在随后的180°C时效处理后，由于大量的β析出物，压缩试样的强度进一步提高，400°C和0.2s-1压缩后时效的试样峰值显示UTS为364 MPa，PS为248 MPa，伸长率为7.7%。
During hot compression, Mg17Al12(β) precipitates show strong influence on the microstructural changes of 415°C-24h homogenized AZ91 alloy. When compressed at 300°C and 350°C, dynamic recrystallization (DRX) only occurs near grain boundaries with discontinuous β precipitate pinning at the newly DRXed grain boundaries. With increasing compression temperature and decreasing strain rate, the β-precipitating region expands; however, the amount of pinning precipitates decreases, resulting in increases in the DRX ratio and average DRXed grain size. With a compression ratio of only 50%, the specimen compressed at 350°C and a strain rate of 0.2s−1(designated 350°C-0.2s−1compressed specimen) shows an ultimate tensile strength (UTS) of 334MPa, a 0.2% proof stress (PS) of 195MPa and an enough elongation of 17.9%. After a subsequent aging treatment at 180°C, due to the large number of β precipitates, the strength of the compressed specimens are further improved, and the specimen peak aged after compression at 400°C and 0.2s−1shows UTS of 364MPa and PS of 248MPa with a moderate elongation of 7.7%.