在modifiedψ -衍射几何条件下 ,研究铍材表层中存在不同应力梯度时d～ (sinψ) 2 曲线的形状 ,确定铍材表面层应力梯度对常规X -射线应力测试的影响。结果表明 ,在 (sinψ) 2 ≤ 0 .5范围内 ,应力梯度对测量结果有明显影响 ,应力测试值因应力梯度存在而偏离真实值。使用钒靶材和大的倾角降低X 射线对铍材的穿透深度 ,可以减小由应力梯度引起的应力测试误差 Under the modified ψ - diffraction geometry, the shape of d sin sin 2 curves in the presence of different stress gradients in the surface layer of beryllium was investigated to determine the effect of the stress gradient on the beryllium surface to the conventional X - ray stress testing. The results show that in the range of (sinψ) 2 ≤0.5, the stress gradient has a significant effect on the measurement results. The stress test value deviates from the true value due to the stress gradient. Using vanadium targets and large dip angles to reduce the penetration depth of X-rays into the beryllium material can reduce the stress test error caused by the stress gradient