Machining of Metal Matrix Composite - process modelling, tool wear and surface integrity

在过去的几十年里，金属基复合材料(MMC)在包括汽车和航空航天在内的几个制造业领域受到了极大的关注，这两个行业是加拿大制造业经济的主要组成部分。与非增强合金相比，金属基复合材料具有更好的物理和机械性能。因此，在许多工程应用中，它们被认为是传统合金的替代材料。其独特的物理性能赋予了它们巨大的潜力，然而，要想让MMCs广泛地替代整体材料，MMCs面临着挑战。在机械加工过程中，韧性基体中的磨料强化会导致严重的刀具磨损和过早的刀具失效。虽然已经努力通过铸造或热锻造来生产MMCs零件，但所得到的近净形状的产品仍然必须以所需的精度被加工成最终的形状和尺寸。加筋颗粒的开裂和剥离是机械加工表面的重要损伤模式，亚表面损伤评估是机械加工构件疲劳损伤评估的关键，尤其是在航空航天等关键领域。已加工表面物理性能和加工残余应力的变化可归因于机械载荷和热载荷(产生的热)。克服这一挑战的一种方法是减少/消除刀具磨损的有害影响。自走式回转刀具此前在切割其他难加工材料时的成功应用，使其成为在切割MMC时更好地控制刀具磨损和刀具寿命的良好候选者。*鉴于这些材料的应用日益广泛，需要对其加工表面完整性进行详细研究，并提高其切割过程效率。这项研究将通过对机械加工的MMC表面进行详细的表面完整性研究，重点研究上述挑战，并提供所需的知识和专业知识，使这种材料能够在加拿大的几个行业中广泛使用。**

During the past decades, Metal Matrix Composites (MMCs) have received considerable interests in several manufacturing sectors including the automotive and aerospace industries which represent a major sector of the Canadian manufacturing economy. MMCs possess superior physical and mechanical properties compared to non-reinforced alloys. Therefore, they are being considered as a replacement material for the conventional alloys in many engineering applications. Their unique physical properties give them a great potential; however, MMCs face challenges in order to have a wide spread MMCs substitution for monolithic materials. The presence of abrasive reinforcements in the ductile matrix causes severe tool wear and premature tool failure during machining operation. Although efforts have been made to produce MMCs parts by casting, or hot forging, the resulted near net-shape products still have to be machined into the final shape and dimension with the required accuracy. Cracking and debonding of the reinforcement particles are the significant damage modes of machined surface and also the subsurface damage assessment is critical for machined components subjected to fatigue, especially in critical application such as aerospace. The changes in the machined surface physical properties and machining induced residual stresses are attributed to both mechanical as well as thermal load (heat generated). One way to overcome this challenge is by reducing/eliminating the harmful effect of tool wear. The previous successful application of self-propelled rotary tool in cutting other difficult to cut materials has made it a good candidate for better control of tool wear and tool life when cutting MMC.***          In view of the growing application of these materials, the detailed study of their machined surface integrity and improvement of their cutting process efficiency is required. This study will focus on the above mentioned challenges through detailed surface integrity study of machined MMC surfaces and provide the needed knowledge and expertise to enable the wide use of this material in several Canadian industries.  **