Machining of metal matrix composites and attainable surface integrity

在过去的几十年里，金属基复合材料（MMC）在几个制造业部门，包括汽车和航空航天工业，代表了加拿大经济的主要部门，受到了相当大的兴趣。 MMC具有上级的物理和机械性能相比，非增强合金。 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。其独特的物理性能使其具有巨大的发展潜力，然而，要使其广泛地替代单片材料，MMC面临着挑战。 韧性基体中磨料增强物的存在导致严重的刀具磨损和加工操作期间的刀具过早失效。 尽管已经努力通过铸造或热锻造来生产金属基复合材料，但是所得到的近净形产品仍然必须被机加工成设计的形状和尺寸。 增强颗粒的开裂和脱粘是机械加工表面的重要损伤模式，亚表面损伤评估对于经受疲劳的机械加工部件是至关重要的，特别是在航空航天等关键应用中。机械加工表面的物理性能和机械加工引起的残余应力的变化归因于机械负荷和热负荷（产生的热量）。 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。 以前的成功工作，加工其他难以切削材料与自走旋转刀具已成为一个很好的候选人，以更好地控制刀具磨损和刀具寿命时，切削MMC。

During the past decades, Metal Matrix Composites (MMC) have received considerable interest in several manufacturing sectors including automotive and aerospace industries which represent a major sector of the Canadian economy. MMC possess superior physical and mechanical properties compared to nonreinforced alloys. Therefore they are being considered as a replacement material for the conventional alloys in many engineering applications. Their unique physical properties gave them a great potential, however, MMC faces 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 by casting, or hot forging, the resulted near net-shape products still have to be machined into the designed shape and dimension. Cracking and debonding of the reinforcement particles are the significant damage modes of machined surface also, 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 work of machining other difficult to cut materials with self propelled rotary tools has made it a good candidate for better control of tool wear and tool life when cutting MMC.