add this code in functions.php file
add_filter( 'the_title', 'ta_modified_post_title');
function ta_modified_post_title ($title) {
global $post;
$mynewdate = strtotime($post->post_date);
$title = $title.'<span class="modified">'.date('Y',$mynewdate).'</span>'.'-<span class="modified">'.date('d',$mynewdate).'</span>-'.'<span class="modified">'.date('m',$mynewdate).'</span>';
return $title;
}
modify date by your own way.