STRENGTHENING MECHANISMS IN ALUMINUM-CERAMIC PARTICLE COMPOSITE ALLOYS PRODUCED BY MECHANICAL ALLOYING
STRENGTHENING MECHANISMS IN ALUMINUM-CERAMIC PARTICLE COMPOSITE ALLOYS PRODUCED BY MECHANICAL ALLOYING
复制标题
机械合金化生产的铝陶瓷颗粒复合合金的强化机制
DOI：
10.2355/isijinternational.32.902
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发表时间：
1992
影响因子：
1.8
通讯作者：
T. Yakou
中科院分区：
文献类型：
--
作者：
T. Hasegawa;T. Miura;Tohru Takahashi;T. Yakou
从显微组织角度分析了机械合金化制备的粉末冶金铝陶瓷颗粒复合合金的室温屈服强度，该合金具有位错密度高（1014 m-2量级）、细小Al4C3和Al2O3颗粒（尺寸35 nm）和粗陶瓷颗粒（0.4-1.0 μm）均匀分散、晶粒尺寸小（0.5 μm）等特点。屈服强度的很大一部分（超过80%）被认为是通过细颗粒的弥散硬化和粗颗粒的颗粒强化而贡献的；对于给定的颗粒体积分数，通过前一种机制的贡献大于通过后一种机制的贡献。前一种机制是基于将细颗粒处的钉扎位错与细颗粒分离，而后一种机制是通过粗颗粒周围的机械约束来限制基体变形。铝基体中的杂质对强度的贡献不大，可能是通过固溶硬化实现的。这些机制额外提高了强度。由于加工过程中引入的高密度位错而导致的加工硬化以及由于小晶粒尺寸而导致的晶界强化被认为不是决定屈服强度的主要机制。
Room-temperature yield strength of powder-metallurgy Al-ceramic particle composite alloys produced by mechanical alloying was analyzed from a viewpoint of microstructure which was characterized by several features: high dislocation density (in the order of 1014 m–2), uniform dispersion of fine Al4C3 and Al2O3 particles (35 nm in size) and coarse ceramic particles (0.4-1.0 μm), and small grain size (0.5 μm). A large portion (more than 80%) of yield strength was concluded to be contributed through dispersion hardening by the fine particles and particle reinforcing by the coarse particles; the contribution was greater through the former mechanism than through the latter one for a given volume fraction of particles. The former mechanism was based on detaching pinned-down dislocations at the fine particles from them, and the latter one on restricting matrix deformation by mechanical constraint around the coarse particles. Impurities in the Al matrix made a modest contribution to strength, probably through solution hardening. These mechanisms raised the strength additively. Work hardening due to a high density of dislocations introduced during processing and grain boundary strengthening due to small grain size were considered not to be principal mechanisms for determining the yield strength.