I haven't tested this, but in my head it works perfectly! What we do is put add a `pre_get_posts` filter in our functions file then get the current user. IF user **isn't** registered, drop out. IF the number of user posts **isn't** greater than 0, drop out. IF we're **not** on the post type archive, drop out. IF all 3 conditions **are true**, we'll replace our default blog articles with the users.

    function user_posts_filter($query){
    	$userID = get_current_user_id();
    	
    	if($userID != 0 && count_user_posts($userID) > 0 && is_post_type_archive('blog')){
    		$query->set('post_type', 'articles');
    		$query->set('author', $userID);
    	}
    }
    add_action('pre_get_posts', 'user_posts_filter');

Hopefully it works for you!