塑性变形对原位zrb22024al复合材料力学性能影响研究.doc

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摘要：本文采用熔体原位反应法制备原位颗粒增强ZrB2/2024铝基复合材料，工艺简单，制备成本低，易推广，但是由于铸造缺陷的存在以及铸造条件的限制，其结构性能不高，增强相尺寸、形貌、在基体合金中分布均匀性不理想。因此对复合材料进行了搅拌摩擦塑性加工，改善复合材料的微观结构，提高材料内部结构的致密性，减少铸造缺陷，从而提高材料的综合性能。通过金相显微镜镜（OM）、X射线衍射仪(XRD)、扫描电子显微镜镜（SEM）等分析设备， 研究搅拌摩擦加工对颗粒增强ZrB2/2024铝基复合材料微观结构及性能的影响。

对铸态复合材料的微观形貌进行研究，发现制备的复合材料中ZrB2颗粒较大。搅拌摩擦后的ZrB2/2024铝基复合材料的微观组织表明，搅拌摩擦后复合材料获得了较细晶粒（3~9μm），增强颗粒弥散分布，团聚现象消除。硬度、摩擦磨损性能都得到了提升。 

搅拌摩擦加工后，基体晶粒破碎，变得细小，晶粒形状也发生了改变；材料的抗拉强度变大（由160MPa到220MPa）、延伸率变大（由8.05%到17.4%），韧性断裂明显；硬度变大（由38.00HBW 到76.94HBW）。摩擦系数随载荷的增加而不断升高，而且变化逐步趋于稳定，说明搅拌摩擦后的复合材料具有较好的摩擦稳定性。

关键词：塑性变形；搅拌摩擦加工；复合材料；力学性能；摩擦磨损；

 

Effects of plastic deformation on in situ ZrB2 / 2024Al Mechanical Properties

Abstract：This article was prepared using a melt-situ reaction in situ particle reinforced ZrB2 / 2024 aluminum matrix composites, simple process, low production cost, easy to promote, but due to the conditions and restrictions casting casting defects, and its structure is not high performance, enhanced - size, shape, uniformity is not satisfactory in the matrix alloy. Therefore, composite materials were plastic friction stir processing, improve the microstructure of composite materials to improve the internal structure of dense material, reducing casting defects, thereby improving the overall performance of the material. By optical microscope lens (OM), X-ray diffraction (XRD), scanning electron microscope microscope (SEM) and other analytical equipment, research FSP particle Reinforced ZrB2 / 2024 aluminum matrix composite microstructure and properties.

  Cast microstructure of the composite material, and found that a composite material in ZrB2 larger particles. Microstructure ZrB2/2024 aluminum matrix composites friction stir after the show, after friction stir composites obtained finer grains (3~9μm), reinforcing particles dispersed, agglomeration eliminated. hardness, friction and wear properties have been improved.

  After stirring friction processing, matrix grain crushing, becoming tiny, grain shape has changed; the tensile strength of the material becomes larger (by a 160MPa to 220MPa), elongation increases (from 8.05% to 17.4%), plastic fracture is obvious; hardness increases (by the 38.00HBW to 76.94HBW).With the increase of the friction coefficient and the load rising, but changes gradually stabilized, after friction stir described composite having good friction stability.

Keywords：Plastic deformation; friction stir processing; composite; mechanical properties; friction and wear;