上海交通大学：《材料组织结构表征》课程教学资源（课件讲义）X射线衍射7-应力分析

七、X射线应力测定

七、X射线应力测定

General stress/strain effects Chinese magic mirror in Han Dynasty(200 B.C.-200 A.D.) The first deliberate use of residual stresses and strains. 2

General stress/strain effects 2 Chinese magic mirror in Han Dynasty (200 B.C. – 200 A.D.) The first deliberate use of residual stresses and strains

Channel crack Low-k dielectric Copper (OSG) interconnect line KFAB1.0kV4.4mm×15.0ksEU)5/19/2000 3.00um Channel cracking,a fracture mode in which through-film cracks propagate in the film due to a tensile residual stress OGS:organosilicate glass The above picture is of a new pressure vessel that failed during its hydraulic test.The vessel had been stress relieved,but some parts of it did not reach the required temperature and consequently did not experience adequate tempering.This coupled with a small hydrogen crack,was sufficient to cause catastrophic failure under test conditions.It is therefore important when considering PWHT or its avoidance,to ensure that all possible failure modes and their consequences are carefully considered before any action is taken 3

3 Channel cracking, a fracture mode in which through-film cracks propagate in the film due to a tensile residual stress OGS: organosilicate glass The above picture is of a new pressure vessel that failed during its hydraulic test. The vessel had been stress relieved, but some parts of it did not reach the required temperature and consequently did not experience adequate tempering. This coupled with a small hydrogen crack, was sufficient to cause catastrophic failure under test conditions. It is therefore important when considering PWHT or its avoidance, to ensure that all possible failure modes and their consequences are carefully considered before any action is taken

七、X射线应力分析 ·应力-应变的基本特征 ·宏观应力 ·微观应变/应力

七、X射线应力分析 • 应力-应变的基本特征 • 宏观应力 • 微观应变/应力 4

应力-应变间关联 ·应力o(stress)→应变&(strain)→晶面间 Ad (change of lattice spacing) △d △d △λ△0cos0 d d sinθ ·线弹性假设下，Hook'slaW:o=Eor=G 通过测定物体中的应变从而确定其应力大 小。 5

应力-应变间关联 • 应力 (stress)  应变 (strain)  晶面间 距d (change of lattice spacing) • 线弹性假设下，Hook’s law: =E or =G • 通过测定物体中的应变从而确定其应力大 小。      sin  cos     d d d d  ~ 5

均匀应变对衍射峰的影响 No lattice strain d。 Uniform lattice strain 精确测定峰位 6

均匀应变对衍射峰的影响 精确测定峰位 6

不均匀应变对衍射峰的影响 No lattice strain tension compression : Non-uniform lattice strain 精确测定峰形 7

不均匀应变对衍射峰的影响 精确测定峰形 7

内应力的分类 第类应力，应力 的平衡范围为宏观 尺寸 ·第川类内应力，应 力的平衡范围为晶 粒尺寸 第川类应力，应力 的平衡范围为单位 晶胞 品界 内应力分类的示意图 8

内应力的分类 • 第I类应力，应力 的平衡范围为宏观 尺寸 • 第II类内应力，应 力的平衡范围为晶 粒尺寸 • 第III类应力，应力 的平衡范围为单位 晶胞 8

七、X射线应力分析 。应力-应变的基本特征 ·宏观应力 ·微观应变/应力 9

七、X射线应力分析 • 应力-应变的基本特征 • 宏观应力 • 微观应变/应力 9

宏观残余应力(1st类) =0° =45° 180°-2 入射 衍射 同族 拉应力 晶面 晶面间距d大 晶面间距d小 工二 拉应力 衍射角2B小 衍射角2B大 压应力？ 10

宏观残余应力(1st类) 压应力? 10