图2.59(a)为Cu与Cu₉Al₄界面的TEM像，在图a左侧为Cu基体，右侧为Cu₉Al₄。在此位置得到的HRTEM像，我们对其同样进行了FFT和IFFT转变，得到图2.59（b）和图2.59（c）。在IFFT图2.59b上侧为Cu晶面右下侧为Cu₉Al₄晶面，可以看出两相具有较好的共格。为验证这一观点，在Cu₉Al₄/Cu界面HRTEM像中经FFT转变得到的图2.59（c）中标出了Cu₉Al₄的（100）（660）晶面和Cu的（331）（420）晶面，并查询PDF卡片得到Cu₉Al₄与Cu的晶面间距分别为dCu₉Al₄(100)(660)=0.7944、1.0256nm和dCu(331)(420)=0.8293、0.8083nm，并在图(b)中进行了标定。通过公式（1）计算得到Cu₉Al₄(100)/Cu(331)晶格失配率为0.042，Cu₉Al₄(660)/Cu(331)晶格失配率为0.236，Cu₉Al₄(100)/Cu(420)的晶格失配率为0.017，Cu₉Al₄(660)/Cu(420)的晶格失配率为0.268。所以此界面具有完全的半共格界面，再次验证上面的观点，相较于钎缝其他界面此界面具有最好的的晶格匹配。

Fig. 2.59(a) shows the TEM image of the interface between Cu and Cu9Al4, with Cu matrix on the left and Cu9Al4 on the right.The HRTEM image obtained at this position was also transformed by FFT and IFFT, and Fig. 2.59 (b) and Fig. 2.59 (c) were obtained.In Figure 2.59b of IFFT, the upper side is the Cu crystal plane and the lower right side is the Cu9Al4 crystal plane. It can be seen that the two phases have good co-lattice.To verify this point of view, the (100) (660) crystal faces of Cu9Al4 and (331) (420) crystal faces of Cu are marked in Fig. 2.59 (c) obtained by FFT transformation in the HRTEM images of Cu9Al4/Cu interface.By querying PDF card, the crystal plane spacing of Cu9Al4 and Cu was obtained as DCu9Al4 (100)(660)=0.7944 and 1.0256nm, and DCu (331)(420)=0.8293 and 0.8083nm, respectively, which were calibrated in Fig. (b).The lattice mismatch ratio of Cu9Al4(100)/Cu(331) is 0.042, the lattice mismatch ratio of Cu9Al4(660)/Cu(331) is 0.236, and the lattice mismatch ratio of Cu9Al4(100)/Cu(420) is 0.017.The lattice mismatch ratio of Cu9Al4(660)/Cu(420) is 0.268.Therefore, this interface has a complete semi-coherent interface, which verifies the above viewpoint again. Compared with other interfaces of brazing joints, this interface has the best lattice matching.