CN117110105A - 通过疲劳断口微观组织分析板材性能的方法 - Google Patents

通过疲劳断口微观组织分析板材性能的方法 Download PDF

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CN117110105A
CN117110105A CN202311365940.6A CN202311365940A CN117110105A CN 117110105 A CN117110105 A CN 117110105A CN 202311365940 A CN202311365940 A CN 202311365940A CN 117110105 A CN117110105 A CN 117110105A
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冯飞
乐开白
刘春华
陈晓辉
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Equipment Design and Testing Technology Research Institute of China Aerodynamics Research and Development Center
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Abstract

本发明属于材料微观组织分析领域,具体公开了通过疲劳断口微观组织分析板材性能的方法,包括利用低周疲劳实验机,对激光选区熔化试件进行不同温度条件下低周疲劳性能测试,采用应变对称加载控制方式;和对典型不同温度和应变幅对应的失效断口进行微观表征测试;本发明利用增材制造设备打印304不锈钢台阶梯形试板制作试件,开展激光选区熔化试件疲劳断口微观组织分析;主要利用扫描电子显微镜和透射电镜分析检测手段来观察温度相关的疲劳断口特征,分析材料晶粒取向、局部应变、滑移带位置和方向及夹杂对疲劳失效行为的影响规律。分析疲劳断口并表征服役过程微观结构演化,总结微观结构与疲劳性能之间的影响关系。

Description

通过疲劳断口微观组织分析板材性能的方法
技术领域
本发明涉及材料测试领域,具体讲是通过疲劳断口微观组织分析板材性能的方法。
背景技术
材料性能的测试是材料投入使用或使用中判断使用寿命的关键手段,而材料性能的测试目前是采用机械方法施加恒定变形(或力)在被测试材上,测得相应的载荷(或变形),由计算机系统计算出试材的弹性模量和抗弯强度,并可用于成材的在线应力分析。通过这种方式的计算误差大,精确度小。
发明内容
因此,为了解决上述不足,本发明在此提供通过疲劳断口微观组织分析板材性能的方法,利用增材制造设备打印304不锈钢台阶梯形试板制作试件,开展激光选区熔化试件疲劳断口微观组织分析;主要利用扫描电子显微镜和透射电镜分析检测手段来观察温度相关的疲劳断口特征,分析材料晶粒取向、局部应变、滑移带位置和方向及夹杂对疲劳失效行为的影响规律。分析疲劳断口并表征服役过程微观结构演化,总结微观结构与疲劳性能之间的影响关系。
通过疲劳断口微观组织分析板材性能的方法,具体方法如下:
S100、利用低周疲劳实验机,对激光选区熔化试件进行不同温度条件下低周疲劳性能测试,采用应变对称加载控制方式;
S200、完成步骤S100后,对典型不同温度和应变幅对应的失效断口进行微观表征测试;
所述步骤S200的具体方法是:
利用扫描电子显微镜观察断口位置特征包括裂纹萌生和扩展区域特征,研究材料晶粒取向、局部应变、滑移带位置和方向及夹杂对疲劳裂纹萌生和扩展行为的影响规律;
利用透射电镜分析检测手段从纳米尺度观察裂纹萌生区域特征,包括第二相、位错滑移、夹渣对裂纹萌生的影响和作用机制,探讨与温度相关微观结构与疲劳性能构效关系。
具体的,所述步骤S100的具体步骤如下:
S101、选用实验设备;
S102、确定实验方法与试件尺寸;
S103、低周疲劳实验结果分析。
具体的,所述步骤S101的具体方法是,选用低周疲劳实验机,进行应变对称加载控制并带加热炉,加热炉精度为正负5℃,实验中实时记录测试数据并能保存输出。
具体的,所述步骤S102的具体方法是,使用金属材料疲劳试验轴向应变控制方法进行低周疲劳实验,低周实验过程中加载波形为三角波,根据材料特性和试件尺寸按指定频率或应变速率来控制波形;
为确保与罐体所用相同材料,应在罐体上进行取样或采取与服役材料相同的后热处理工艺。
所述试件为狗骨头型圆棒,具体尺寸应根据材料属性进行微调,试件表面粗糙度不小于0.6。
具体的,所述低周疲劳实验测试温度分别选择为室温、300℃及650℃,在达到指定温度后保温20min使试件内部温度达到均匀再开始实验;采取对称拉-压加载方式,应变幅范围为0.4%-1.0%,利用引申计来实时监测测试过程试件应力和应变情况,并在电脑上进行记录,每个应变幅下测试2-3个样品,测试停止条件为达到目标寿命周次停止或试件在目标周次内发生失效自动停止。
具体的,所述步骤S103的具体方法是,实验完成后,对不同温度的低周实验结果数据进行分析处理,获得与温度和应变幅相关的循环响应特征曲线,分析裂纹萌生、扩展及最终断裂时循环演化特征,揭示温度对低周疲劳行为尤其是裂纹萌生及扩展的影响和作用机制;揭示温度对低周疲劳过程的塑性演化与能量耗散分布的影响,从塑性和能量耗散角度阐述温度相关低周失效行为。
本发明具有如下有益效果:
本发明主要利用扫描电子显微镜和透射电镜分析检测手段来观察温度相关的疲劳断口特征,分析材料晶粒取向、局部应变、滑移带位置和方向及夹杂对疲劳失效行为的影响规律。分析疲劳断口并表征服役过程微观结构演化,总结微观结构与疲劳性能之间的影响关系。所述低周疲劳实验测试至少实施三种温度(室温、300℃、650℃)的低周疲劳,即三条SN曲线,试样数量不少于30个。并且通过本发明所述的方法,可以让不同的检测人员对同一试件的检测结果一致,不存在分歧。
附图说明
图1是本发明的流程示意图;
图2是本发明所述步骤S100的流程示意图;
图3是所述低周疲劳试验中加载的波形示意图;
图4是低周疲劳实验的试件尺寸示意图;
图5是温度和应变幅相关循环滞后特征曲线;
图6是温度和应变幅相关循环滞后特征曲线;
图7是SEM疲劳断口微观表征示意图;
图8是TEM疲劳断口微观表征示意图。
具体实施方式
下面将结合附图1-图5对本发明进行详细说明,对本发明实施例中的技术方案进行清楚、完整地描述,显然,所描述的实施例仅仅是本发明一部分实施例,而不是全部的实施例。基于本发明中的实施例,本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例,都属于本发明保护的范围。
在材料测试中,目前采用机械方法施加恒定变形(或力)在被测试材上,测得相应的载荷(或变形),由计算机系统计算出试材的弹性模量和抗弯强度,并可用于成材的在线应力分析;但是通过这种方式的计算误差大,精确度小。
基于该问题,本实施例在此提供了通过疲劳断口微观组织分析板材性能的方法,包括如下步骤:
步骤S100、利用低周疲劳实验机,对激光选区熔化试件(该试件为风洞中的材料,对温度变化承受力大、强度要求高)进行不同温度条件下低周疲劳性能测试,采用应变对称加载控制方式,温度分别为室温、300℃及650℃。
步骤S200、实验完成后,对典型不同温度和应变幅对应的失效断口进行微观表征测试。
具体的,所述步骤S100包括如下步骤:
步骤S101、实验设备,
选用低周疲劳实验机,可以进行应变对称加载控制并带加热炉,加热炉精度为正负5℃,实验中实时记录测试数据并能保存输出。
步骤S102、实验方法与试件尺寸
根据金属材料疲劳试验轴向应变控制方法进行低周疲劳实验,低周实验过程中加载波形为三角波,如图3所示,根据材料特性和试件尺寸按一定频率或应变速率来控制波形。
为确保与罐体所用相同材料,应在罐体上进行取样或采取与服役材料相同的后热处理工艺。试件形状为狗骨头型圆棒,尺寸示意图如图4所示,具体尺寸应根据材料属性进行微调。试件表面粗糙度不小于0.6。
低周疲劳实验测试温度分别选择为室温、300℃及650℃,在达到指定温度后保温20min使试件内部温度达到均匀再开始实验。采取对称拉-压加载方式(R=-1),应变幅范围为0.4%-1.0%,利用引申计来实时监测测试过程试件应力和应变情况,并在电脑上进行记录,每个应变幅下测试2-3个样品,测试停止条件为达到目标寿命周次停止或试件在目标周次内发生失效自动停止。
步骤S103、实验结果分析
实验完成后,对不同温度的低周实验结果数据进行分析处理,获得与温度和应变幅相关的循环响应特征曲线,如图5所示,分析裂纹萌生、扩展及最终断裂时循环演化特征,揭示温度对低周疲劳行为尤其是裂纹萌生及扩展的影响和作用机制;与温度和应变幅相关的循环滞后曲线,如图6所示,揭示温度对低周疲劳过程的塑性演化与能量耗散分布的影响,从塑性和能量耗散角度阐述温度相关低周失效行为。
具体的,所述步骤S200的具体方法是,实验完成后,对典型不同温度和应变幅对应的失效断口进行微观表征测试。
利用扫描电子显微镜(SEM)观察断口位置特征包括裂纹萌生和扩展区域特征,如图7所示(图中△框选处为二次裂纹,○框选处是疲劳条纹),系统研究材料晶粒取向、局部应变、滑移带位置和方向及夹杂对疲劳裂纹萌生和扩展行为的影响规律;利用透射电镜(TEM)分析检测手段从纳米尺度观察裂纹萌生区域特征,包括第二相、位错滑移、夹渣等对裂纹萌生的影响和作用机制,如图8所示(□中框选处是混乱位错,六边形框选处是错位),探讨与温度相关微观结构与疲劳性能构效关系。激光选区熔化板材试件疲劳断口微观组织分析的无损检测技术适应性评价时间节点及相关操作人员见表1所示。
表1 激光选区熔化疲劳断口微观组织分析无损检测技术适应性评价时间节点及人员
本实施例所述的方法是利用低周疲劳实验机,进行不同温度条件下低周疲劳性能测试,采用应变对称加载控制方式,温度分别为室温、300℃及650℃。主要利用扫描电子显微镜和透射电镜分析检测手段来观察温度相关的疲劳断口特征,分析材料晶粒取向、局部应变、滑移带位置和方向及夹杂对疲劳失效行为的影响规律。分析疲劳断口并表征服役过程微观结构演化,总结微观结构与疲劳性能之间的影响关系。
对所公开的实施例的上述说明,使本领域专业技术人员能够实现或使用本发明。对这些实施例的多种修改对本领域的专业技术人员来说将是显而易见的,本文中所定义的一般原理可以在不脱离本发明的精神或范围的情况下,在其它实施例中实现。因此,本发明将不会被限制于本文所示的这些实施例,而是要符合与本文所公开的原理和新颖特点相一致的最宽的范围。

Claims (6)

1.通过疲劳断口微观组织分析板材性能的方法,其特征在于,包括如下步骤:
S100、利用低周疲劳实验机,对激光选区熔化试件进行不同温度条件下低周疲劳性能测试,采用应变对称加载控制方式;
S200、完成步骤S100后,对典型不同温度和应变幅对应的失效断口进行微观表征测试;
所述步骤S200的具体方法是:
利用扫描电子显微镜观察断口位置特征包括裂纹萌生和扩展区域特征,研究材料晶粒取向、局部应变、滑移带位置和方向及夹杂对疲劳裂纹萌生和扩展行为的影响规律;
利用透射电镜分析检测手段从纳米尺度观察裂纹萌生区域特征,包括第二相、位错滑移、夹渣对裂纹萌生的影响和作用机制,探讨与温度相关微观结构与疲劳性能构效关系。
2.根据权利要求1所述通过疲劳断口微观组织分析板材性能的方法,其特征在于:所述步骤S100的具体步骤如下:
S101、选用实验设备;
S102、确定实验方法与试件尺寸;
S103、低周疲劳实验结果分析。
3.根据权利要求2所述通过疲劳断口微观组织分析板材性能的方法,其特征在于:所述步骤S101的具体方法是,选用低周疲劳实验机,进行应变对称加载控制并带加热炉,实验中实时记录测试数据并能保存输出。
4.根据权利要求2所述通过疲劳断口微观组织分析板材性能的方法,其特征在于:所述步骤S102的具体方法是,使用金属材料疲劳试验轴向应变控制方法进行低周疲劳实验,低周实验过程中加载波形为三角波,根据材料特性和试件尺寸按指定频率或应变速率来控制波形;
所述试件为狗骨头型圆棒,具体尺寸根据材料属性确定,试件表面粗糙度不小于0.6。
5.根据权利要求4所述通过疲劳断口微观组织分析板材性能的方法,其特征在于:所述低周疲劳实验测试温度分别选择为室温、300℃及650℃,在达到指定温度后保温20min使试件内部温度达到均匀再开始实验;采取对称拉-压加载方式,应变幅范围为0.4%-1.0%,利用引申计来实时监测测试过程试件应力和应变情况,并在电脑上进行记录,每个应变幅下测试2-3个样品,测试停止条件为达到目标寿命周次停止或试件在目标周次内发生失效自动停止。
6.根据权利要求2所述通过疲劳断口微观组织分析板材性能的方法,其特征在于:所述步骤S103的具体方法是,实验完成后,对不同温度的低周实验结果数据进行分析处理,获得与温度和应变幅相关的循环响应特征曲线,分析裂纹萌生、扩展及最终断裂时循环演化特征,揭示温度对低周疲劳行为;揭示温度对低周疲劳过程的塑性演化与能量耗散分布的影响,从塑性和能量耗散角度阐述温度相关低周失效行为。
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