摘要
本文以高强韧β钛合金为研究对象,研究了喷丸强度、弹丸介质(铸钢丸和陶瓷丸)及复合喷丸对靶材疲劳性能的影响。采用扫描电镜、X射线衍射仪等设备表征,分析了喷丸工艺对试样表面完整性及疲劳断裂的影响。试验表明,喷丸处理能有效改变靶材表面机加工轮廓,随着喷丸强度增加(最大至0.25 mmA),表面粗糙度升高,但没有出现脱层或微裂纹缺陷,表明靶材塑韧性好。然而,靶材表面对覆盖率较为敏感,复合喷丸处理(覆盖率400%)表面局部出现脱层和褶皱缺陷。喷丸在靶材表面引入深约280μm的残余压应力层,随喷丸强度增加,残余应力值整体增加,但喷丸强度达到0.22 mmA时,近表层(50μm厚)出现应力松弛。喷丸强化后疲劳性能提升显著,在铸钢丸条件下疲劳寿命较原始态可提高145.4倍,个别试样疲劳寿命达到107次。相同喷丸强度下陶瓷喷丸疲劳性能提升更显著。单一弹丸介质喷丸处理后裂纹源均转移至次表层。复合喷丸平均疲劳寿命大幅降低,部分裂纹源出现在表面,归因于表面损伤和残余应力松弛。高强韧β钛合金喷丸强化效果较好,对喷丸强度敏感性低、不易出现脱层或微裂纹缺陷,但对喷丸覆盖率较为敏感,不适用于复合喷丸或长时间喷丸处理。
This study investigates the effects of shot peening intensity,shot medium(cast steel shot and ceramic shot),and composite shot peening on the fatigue properties of high-strength and high-toughnessβ-titanium alloy.Characterization techniques,including scanning electron microscopy(SEM)and X-ray diffractometry(XRD),were employed to analyze the influence of shot peening processes on the surface integrity and fatigue fracture behavior of target materials.Experimental results show that shot peening effectively modifies the machined surface profile of target materials.With the increase of shot peening intensity(up to 0.25 mmA),surface roughness increases,yet no delamination or micro-crack defects are observed,indicating excellent plasticity toughness of the target materials.However,the surface of target materials is sensitive to coverage:Local delamination and wrinkling defects occur on the surface after composite shot peening with 400%coverage.Shot peening introduces a residual compressive stress layer approximately 280μm in depth on the surface of target materials.The residual stress value generally increases with shot peening intensity,but stress relaxation occurs in the near-surface layer(50μm thickness)when the intensity reaches 0.22 mmA.Shot peening significantly enhances fatigue performance:Under cast steel shot peening conditions,the fatigue life increases by 145.4 times compared to the as-received state,with individual specimens reaching 1×107 cycles.Ceramic shot peening demonstrates more pronounced fatigue improvement at the same intensity.For peening with a single-shot medium,crack initiation sites shift to the subsurface layer,whereas composite shot peening reduces the average fatigue life significantly,with some crack sources appearing on the surface,attributed to surface damage and residual stress relaxation.In conclusion,high-strength and high-toughnessβ-titanium alloy exhibits favorable shot peening performance,low sensitivity to shot peening intensity(resistant to delamination or microcrack),but high sensitivity to shot peening coverage,making it unsuitable for composite or extended shot peening treatments.
作者
林鑫
盖鹏涛
周文龙
陈国清
李春艳
付雪松
LIN Xin;GAI Pengtao;ZHOU Wenlong;CHEN Guoqing;LI Chunyan;FU Xuesong(Dalian University of Technology,Dalian 116024,China;AVIC Manufacturing Technology Institute,Beijing 100024,China)
出处
《航空制造技术》
北大核心
2025年第19期128-135,共8页
Aeronautical Manufacturing Technology
基金
国家自然科学基金(51975084)
辽宁省自然科学基金(2022-YKLH-04)
辽宁省“兴辽英才计划”项目(XLYC1902084)
中央高校基本科研业务费专项(DUT19LAB16)。
关键词
高强韧钛合金
弹丸介质
残余应力
疲劳寿命
疲劳断口
High-strength and high-toughness titanium alloy
Shot medium
Residual stress
Fatigue life
Fatigue fracture
