Effect of TiB 2 Particles on Microstructure of 7075 Al Alloy in Semi-Solid State Near Liquidus
Effect of TiB 2 Particles on Microstructure of 7075 Al Alloy in Semi-Solid State Near Liquidus
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DOI：
10.2320/matertrans.m2014447
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发表时间：
2015-11
影响因子：
1.2
通讯作者：
Gui-Sheng Gan;Huaishan Wang;G. Meng;Bin Yang
中科院分区：
文献类型：
--
作者：
Gui-Sheng Gan;Huaishan Wang;G. Meng;Bin Yang
采用原位反应法制备了TiB 2/7075 Al基复合材料，研究了TiB 2颗粒含量对7075 Al合金近液相线半固态组织的影响。结果表明，随着TiB 2含量的增加，合金的平均晶粒尺寸逐渐减小，显微组织变为均匀的玫瑰花状晶粒。当颗粒含量大于4.5mass%时，晶粒形貌变为粗大的枝晶。7075铝合金在630°C下保温7.5min，可获得尺寸达94μm的球状晶粒。在630°C下，3mass%TiB2/7075、4.5mass%TiB2/7075和9mass%TiB2/7075铝基复合材料在30 min、20 min和50 min时的最小晶粒尺寸分别为88μm、51μm和69μm。TiB 2颗粒位于晶界，阻碍了Al原子在7075铝合金半固态内的扩散，抑制了-Al相的长大，但有利于提高近液相线触变成形半固态浆料的稳定性。[doi：10.2320/matertrans.M2014447]
TiB2/7075 Al matrix composites were formed by in situ reaction, and effect of the TiB2 particles content on microstructure of 7075 Al alloy in semi-solid state near liquidus were investigated. The results have shown that the average grain size decreased with increased the amount of TiB2, and the microstructure became uniform rosette grains. The morphology of grains became big dendrite grains when the particles content were over 4.5mass%. Globular grains of 7075 Al alloy whose size reached 94μm can be got for 7.5min at 630°C. The minimum grain size of 3mass%TiB2/7075, 4.5mass%TiB2/7075 and 9mass%TiB2/7075 Al matrix composites at 630°C were 88μm, 51μm and 69μm for 30min, 20min and 50min, respectively. The TiB2 particles located in the grain boundary can hinder the Al atoms from diffusing within the semi-solid state of the 7075 Al alloy and restrain ¡-Al phase growth, but it can be conducive to improve the stability of semi-solid slurry in near-liquidus thixoforming. [doi:10.2320/matertrans.M2014447]