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）在几个制造业领域受到了相当大的兴趣，包括汽车和航空航天工业，它们代表了加拿大经济的主要部门。与非增强合金相比，MMC具有优越的物理和机械性能。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。其独特的物理性质使其具有巨大的潜力，然而，要使MMC广泛地取代单片材料，还面临着挑战。在加工过程中，在韧性基体中存在磨粒增强会导致严重的刀具磨损和刀具过早失效。虽然已经努力通过铸造或热锻来生产mmc，但所得到的接近净形状的产品仍然必须加工成设计的形状和尺寸。增强颗粒的开裂和脱粘也是加工表面的重要损伤形式，对受疲劳影响的加工部件进行亚表面损伤评估是至关重要的，特别是在航空航天等关键应用领域。加工表面物理性能的变化和加工引起的残余应力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。以往利用自走式旋转刀具加工其他难切削材料的成功经验，使其成为切削MMC时更好地控制刀具磨损和刀具寿命的理想选择。

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.