Investigation of phase Transformation and Tougning Mechanism of Zirconla/Metal Functional Matrix by Grinding

功能矩阵是未来工业材料中最神奇的复合材料。但是，在生产过程中只有很少的数据。研究了新型氧化锆/镍复合材料的磨削特性。特别是澄清了磨削引起的增韧机理和表面特性对复合材料强度特性的影响。氧化锆/镍复合材料的抗弯强度随着氧化锆含量的增加而增加。由于镍的颗粒尺寸大于氧化锆，裂纹在镍颗粒中传递到断口上。然后，增韧可能是由于大量氧化锆颗粒的裂纹传递。单斜相随着镍含量的增加而增加。在复合材料的冷却过程中，氧化锆的压应力由镍的大收缩引起马氏体转变。随着金刚石磨粒粒度的增大，磨削表面粗糙度和单斜相增大。单斜相的增量速率随氧化锆含量的增加而减小。此外，在富含氧化锆的复合材料中，随着磨粒尺寸的增大，抗弯强度和单斜相增加。另一方面，车轮转速越低，表面粗糙度越大。单斜相和抗弯强度随着车轮转速的增加而增加。这是由于在高速轮速下，冲击力增加了马氏体相变。相反，在镍含量超过50%的复合材料中，随着轮速的增加，单斜相减少，弯曲强度增加。用SD140/170砂轮对抛光后的试样进行残余应力测量。氧化锆部分由残余压应力填充。这些残余应力和单斜相随着镍含量的增加而增加。但是，100%镍的拉伸残余应力存在于其中。这是由于地面的马氏体转变所致。也就是说，氧化锆相变引起的体积膨胀诱发了镍中的残余压应力。少

The functional matrix is the most miracle composite as the future industrial materials. But, there are only a few data in the manufacturing process. Here, the grinding characteristics are investigated for the new product of zirconia/nickel composite. Especiaaly, the influences to its strength characteristics of these composites by the toughening mechanism and surface characteristics induced by grinding are cleared. In zirconia/nickel composite, the bending strength increase with the large constituent rates of zirconia. Because the particle size of nickel is larger than that of zirconia, the crack transmitted in nickel particle on the fracture. Then, the toughening may be due to crack transmission by a lot of zirconia particles. The monoclinic phase increase with the increase of nickel contents. In cooling process of composites, the martensite transformation is induced by the compressive stress of zirconia by the large shrinkage of nickel.The surface roughness and the monoclinic phase o … More n the ground surface increase with the large grits sizes of diamond abrasive grain. The increment rate of monoclinic phase decreases with the large contents of zirconia. Furthermore, in the rich zirconia composite, the bending strength and the monoclinic phase increase with the large size of abrasive grains. On the other hand, the surface roughness increase with the low wheel speed. The monoclinic phase and the bending strength increase with the high wheel speed. This is due to the increase of martensite transformation by the impact force in the high wheel speed. On the contrary, in over 50% nickel composites, the monoclinic phase decrease and the bending strength increase with the high wheel speed in the composites over 50% nickel.The residual stress is measured on the polished sample after grinding with SD140/170 wheel. The part of zirconia is filled by the residual compressive residual stress. These residual stresses and the monoclinic phase increase with the large centents of nickel. But, the 100% nickel reside the tensile residual stress in it. This is due to the martensite transformation on the ground surface. In other word, the volume expansion by the phase transformation of zirconia induced the compressive residual stress in nickel. Less